Preserving User Privacy Through Ephemeral Sharing Design: A Large-Scale Randomized Field Experiment in the Online Dating Context Abstract - CSWIM 2021

Preserving User Privacy Through Ephemeral Sharing Design:
  A Large-Scale Randomized Field Experiment in the Online Dating Context
                                            Abstract

Communication cold-start problems are pervasive in privacy-sensitive settings. To address those
problems, our research examined ephemeral sharing as a privacy-preserving mechanism to
navigate the balance between users’ privacy concerns and information sharing in the initial
interaction stages in online dating. In partnership with Summer, a leading online dating platform,
we report a large-scale randomized field experiment with over 70k users to understand how
ephemeral sharing influences users’ information sharing behavior and subsequent match
outcomes. We find that the subjects in the ephemeral group achieves a significantly larger
number of personal photos along with their matching request, a more significant number of
initial matches, and higher conversational engagement from receivers. Further, our sequential
mediation tests further show that the increased sharing of personal photos is the primary
mechanism. Our study contributes to the literature on the design of matching platforms and
provides actionable implications for the privacy-preserving design of matching platforms.

Keywords: Ephemeral sharing, online dating, privacy-preserving design, information disclosure,
randomized field experiment

1. Introduction
Online dating platforms, such as Bumble, Tinder, and Coffee Meets Bagel, have become
important avenues for individuals to meet and date in recent years. It was reported that almost
40% of young couples met their partners online, and the global users of online dating platforms
are estimated to exceed 441.8 million by 2024 (Rosenfeld et al. 2019; Statista 2020). Given the
outsized role of online dating platforms in the dating market, how to optimally design these
platforms is of crucial interest (Constantinides et al. 2018). Notably, a primary goal of online
dating platforms is to help users find their ideal dates by connecting users with potential dates
and facilitating the subsequent communication between them.
However, a key challenge the online dating platform is plagued with is the communication
cold-start problems, wherein users’ privacy concerns lead to the withholding of personal
information in the initial interactions, which hinders trust-building and consequently effective
communication. Users of online dating platforms are rather secretive and highly concerned about
their privacy (Lutz & Ranzini 2017; Shi & Viswanathan 2020). As they engage in online social
interaction with strangers, users of online dating platforms fear their identity and other sensitive
personal information can be abused by users with ill-intentions (scams and catfishing) (Cobb &
Kohno 2017). Therefore, driven by privacy concerns, users of online dating platforms,
particularly in the initiation phase, often refrain from voluntary sharing of personal information.
For example, many users do not voluntarily provide their personal profile pictures to avoid
revealing their real Identity (Hall et al. 2010). As a result, even if the two partners are matched,
their communication becomes iced.
However, a lack of self-disclosure is debilitating for an online dating platform wherein reducing
information asymmetry between two partners is crucial for a successful match. The users who
provide limited information about themselves are likely dismissed by their prospective dating
partners who also try to avoid connecting and disclosing their personal information to strangers

whom they know little about. Moreover, a lack of personal disclosure can lead to information
asymmetry, such that it is hard to be sure that the user is authentic and trustworthy (John et al.
2016). To address such concerns, digital platforms typically implement reputation systems or
dispute systems (Burtch et al. 2021). However, it is rare for online dating platforms to allow
users to rate or dispute the dating experiences, thus constraining the possibilities of addressing
information asymmetry issues.
To address the communication cold-start problems, we propose a privacy-preserving ephemeral
sharing mechanism for use by dating match senders during their matching requests in online
dating platforms. Ephemeral sharing refers to the digital design that content (usually photos or
video) shared by a sender will be purged shortly after it reaches the intended receiver (Xu et al.
2016). Ephemeral sharing has been previously adopted by social communication platforms such
as Snapchat and Telegram to increase the freedom of self-expression (Vaterlaus et al. 2016). The
literature has shown that ephemeral sharing can affect what they share on social communication
platforms (Piwek & Joinson 2016) and how much users communicate with their social ties
(Bayer et al. 2020). Unlike social communication platforms, online dating platforms use
ephemeral sharing in the match formation phase wherein the two ends are still strangers rather
than between established ties. To our knowledge, the effect of ephemeral sharing on match
formation has not been examined. It is not immediately clear what the effect of ephemeral
sharing on match outcomes would be. On the one hand, by encouraging self-disclosure,
ephemeral sharing may lead to more revelation (e.g., personal photo) about the sender, alleviate
information asymmetry, and facilitate matching. On the other hand, ephemeral sharing can
potentially cause receivers to pay less attention to the request sender due to the limited time the
photo is available. Further, it may even lead to the revelation of unfavorable information,
possibly leaving a negative impression on the receivers (Hofstetter et al. 2017). Beyond the
effect of ephemeral sharing on the match outcomes, we are also interested in whether it addresses
the communication cold-start issue, as a majority of the matches do not lead to further
engagements (Bapna et al. 2016). Bearing the above discussion in mind, our study investigates
the following research questions.
     • How does ephemeral sharing affect information sharing behavior and initial matches
         (i.e., approved matching requests) in online dating platforms?
     • How does ephemeral sharing alleviate communication cold-start problems in online
         dating platforms?
We conduct a large-scale randomized field experiment in partnership with Summer, a leading
online dating platform in China. Our experiment employs a between-subjects, user-level design
with two groups: a control group where sender-shared photos are persistent and a treatment
group where such photos are ephemeral. The subjects are informed by the user interface (UI) of
the request page in the treatment group that the photo they share during a matching request will
be ephemeral (“the photo will only be viewable for five seconds and then no longer available”).
In contrast, subjects in the control group can only upload a regular (i.e., persistent) photo.
Subjects in both groups decide whether to include a photo in each of their matching requests.
Our field experiment generates a series of findings. First, subjects in the treatment (ephemeral
photo) group send more matching requests with personal photos. Besides, these subjects achieve
significantly more initial matches and, more importantly, higher conversational engagement from
the receiver. Second, our causal mechanism tests suggest that the observed effect on the match
outcomes is fully explained by the increases in requests with photos, i.e., the information sharing

promoted by ephemeral sharing. The sequential mediation tests further show that the increased
sharing of personal photos increases the dating request receivers’ conversational engagements.
Our study contributes to the literature on the design of digital platforms and the emerging
literature on ephemeral design. First, our paper is the first to introduce a novel
privacy-preserving design, ephemeral sharing, to encourage the disclosure of personal
information to facilitate better match outcomes on online dating platforms. The ephemeral
sharing design, building on the line of research on privacy-preserving designs, addresses the
privacy-authenticity dilemma as we uncover whether and how this mechanism drives desirable
behavioral change. Second, our paper contributes to the literature on ephemeral sharing (Piwek
& Joinson 2016; Pu et al. 2020). It is among the first to deliberate on the causal impact of
ephemeral sharing in the context of online dating, with a large-scale randomized field experiment
that avoids potential reporting biases and identification concerns. Results from this study
demonstrate that ephemeral sharing can facilitate the formation of initial connections in a
privacy-sensitive setting, such that they are willing to disclose more personal information when
they take the initiative to match in the online dating platforms. The sender’s sharing of personal
photos leads to follow-up conversational engagement from the receivers, thus effectively
addressing the communication cold-start problems in privacy-sensitive settings.
Our research also provides actionable implications for the platforms design privacy-preserving
features. Online dating platforms or other private-sensitive settings can implement the ephemeral
sharing design to encourage users on those platforms self-disclose more with their privacy being
well-preserved, such that those platforms can tackle the communication cold-start problems.
Besides, albeit the ephemeral sharing treatment targets motivating users to distribute personal
photos in our study, it also affords the disclosure of personal information that formats in texts,
audios, and videos.
2. Research Design
Our randomized field experiment employs a user-level, between-subjects design. The experiment
was implemented between February 28 and March 16 in 2020, ending up to 18 days. Each user
on the partner platform was randomly assigned to either the treatment group or the control group
when the user updated the mobile application to Version 3.8.2; the user stayed in the same group
throughout the experiment (i.e., they either always upload persistent photos or always upload
ephemeral photos). To avoid potential contamination, we made sure that no other experiments
were running on the partner platform during the experimentation.
Our experimental stimuli involve the user interface (UI) variations in the matching request page.
Figure 1 and Figure 2 blueprint the manipulation information shown to a subject when landing
on a request page and when uploading a photo in the matching request, respectively. First, as
shown in Figure 1, the connect request UI for the control group invites the subjects to voluntarily
upload a persona photo by stating ‘Upload a personal photo’; instead, the UI for the treatment
group includes an option to ‘Upload a personal photo (ephemeral).’ Second, if the user taps the
button to add a photo, a floating photo-uploading window pops up with more nuanced
differences, as illustrated in Figure 2. First, the treatment UI entitles ‘Upload an ephemeral
photo’ (as opposed to ‘Upload a photo’ in the control UI). Second, the treatment UI for
uploading photos is a variant of the control image, with “burning fire” adjacent to the “photo” in
the image (noting that the phrase “ephemeral” means ‘burn after viewing’ in the Chinese culture).
The treatment description has an additional sentence explaining how the ephemeral photo
functions. Our extensive interviews and pilot tests with users of the partner platform suggest that
the meaning of ‘ephemeral photo’ is delivered appropriately.

Figure 1. Screenshot of the Request Page

Notes: Figure 1 presents the screenshots of the request page with manipulation information (translated)
highlighted in red. The left image is the treatment UI for the matching request page, and the right image is
the control UI for the corresponding page.
                         Figure 2. Screenshot of the Popup on the Request Page

Notes: Figure 2 presents the screenshots popup window after a user taps to upload a photo, with
manipulation information (translated) highlighted in red. The treatment UI situates at the left while the
control UI on the right.
3. Results
3.1 Randomization Checks
Before conducting further analyses, we perform randomization checks across the two groups on
observed covariates. More specifically, we conduct pairwise t-tests on subjects’ gender, age,
education, popularity, tenure, the date since subjects participate in the experiment and

Kolmogorov-Smirnov tests on categorical variables including users’ location (province-level),
school, and major. There are no significant differences across the groups on any of the observed
covariates, such that our experiment was implemented appropriately.
3.2 Main Analyses
To examine whether the ephemeral treatment can result in expected effects, we conduct main
analyses at the user level. The variables of interest are: i) the number of requests with a photo
attached (# Photos), a variable that describes user information sharing behavior, in particular, ii)
the number of initial matches (# Initial Matches), a variable denoting the match outcome, iii) The
total number of messages that a sender receives from the new connections during the experiment,
a variable observing further conversations from the receivers (# Total Receiver Messages). Since
its distribution is highly skewed, we run the regressions with the logarithm as the dependent
variable, i.e., Ln (# Total Receiver Messages). We also include user popularity and demographics
as control variables (gender, age, education, and tenure).
Table 1 reports the results of OLS regressions for the three variables of interest. First, Model 1
demonstrates that the coefficients of Ephemeral on # Photos are significant, positive (βEphemeral =
0.111, p < 0.01). The magnitude of the effect is approximately 52.1%. That is, considering that
the average number of photos shared in the control group is 0.215, an increase of 0.111 takes up
a share of 52.1% in information sharing, which is a significant improvement.
Second, Model 2 indicates that subjects in the treatment group (versus subjects in the control
group) significantly achieve more initial matches (βEphemeral = 0.079, p < 0.01). The size of the
effect is 0.079, approximately a 3% increase in the average initial matches. Accordingly, we
conclude that the ephemeral treatment significantly improves the match outcome.
Model 3 suggests that the subjects in the treatment group (versus subjects in the control group)
do significantly receive more messages from the matches they initiate to establish during the
experiment (βEphemeral = 0.042, p

to perform user-level mediation analyses (Hayes 2017). Figure 3 presents the results of our
mediation analysis. First, the analysis unravels that ephemeral treatment imposes a significant
influence on the number of initial matches through user’s sharing more photos. Specifically, the
direct effect of ephemeral treatment on the number of initial matches is not significant
(Ephemeral → # Initial Matches), with zero included in the 95% confidence interval (CI) (95%
CI∈ [-0.049, 0.113]). Second and more importantly, the 95% CI of the indirect effect, Ephemeral
→ # Photos → # Initial Matches, is significant (95% CI ∈ [0.041, 0.078]).
Besides, the effect of Ephemeral on # Total Receiver Messages is significantly mediated by #
Photo through two paths. The first path (Ephemeral → # Photos → # Initial matches → ln #
Total Receiver Messages) has a 95% CI that does not include zero (95% CI ∈ [0.011, 0.021]),
which suggests that the ephemeral treatment sequentially increase the number of matching
requests with photos, initial matches, and total receiver messages. More importantly, the 95% CI
of the second path (Ephemeral → # Photos → ln # Total Receiver Messages) does not include
zero (95% CI ∈ [0.0001, 0.004]), suggesting that more personal photo sharing can directly make
the receivers more engaged in conversation after successfully matched.
To sum it up, our mediation analysis suggests the information-sharing behavior fully mediates
the effect of the ephemeral treatment on the number of initial matches and the number of receiver
messages. In other words, the mechanism of sharing more personal information completely
explains the process by which the ephemeral treatment affects the match outcomes.
                                Figure 3. Sequential Mediation Analysis

4. Discussions
Our research address a common issue in privacy-sensitive settings, the communication cold-start
problems, as users in online dating platforms typically refrain from sharing their personal
information during the initial interaction phase, making it difficult for the two users who are still
strangers to build up trust. The ephemeral sharing feature we design prompts the sharing of
personal photos along with their matching requests, the effect of which provokes more initial
matches and further increases the conversational engagement from the receivers, effectively
addressing the communication cold-start problems in online dating platforms. As digital
platforms grow, user privacy and data protection are increasingly important (Aridor et al. 2020).
Since users demand privacy and seek to engage anonymously when possible, they become more
and more cautious about their disclosure of personal information, which leads to distrust (John et
al. 2016). It is our hope that our design is one of the many upcoming efforts in designing and
implementing large-scale digital experiments to test effective privacy-preserving mechanisms.

                                   References Upon Request