The recruitment of participants for online survey research presents many challenges. In this work, we present four experiments examining how two different kinds of "surprise" financial incentives affect the rate of participation in a longitudinal study when participants are initially solicited with either an appeal to intrinsic motivation to participate in research or one that also offers extrinsic financial incentives. We find that unexpected financial incentives ("existence surprises") presented to people who click a recruitment advertisement focused on intrinsic incentives lead to a lower recruitment rate than do the same incentives offered to those who clicked an advertisement that led them to expect it. However, when potential participants expect a financial incentive, surprising them with a higher amount ("amount surprises") yields a higher recruitment rate. We interpret these results in the context of crowding theory. Neither type of surprise affected ongoing participation, measured as the number of questions and questionnaires completed over the course of the study.

As a class, online groups are popular, but many die before they become successful. This research traced the fate of 472,231 new online groups. By the end of a 3-month observation period, 57% of the groups had died, ceasing to post new content. Founders' human and social capital before the group was formed, the decisions they made when they created the group and their behavior in the group during its first week all predicted group survival. Many of the results suggest that founders create more successful groups if they have more resources (e.g., more online friends) and opportunities for acquiring relevant skills (e.g., more experience with online groups) and are more active in their group. However, founders who are too controlling seem to present a threat their groups. Their groups are more likely to fail if they are the only group administrator, if they have ties to all group members and if they were responsible for adding all group members.

Research suggests that social network sites can support social capital exchanges, which are often triggered by requests for assistance, such as seeking recommendations or asking for favors. Responsiveness to these requests for help is important to study because these interactions have the potential to affect users' overall satisfaction with the experience of using SNSs, signal social grooming functions that are an essential part of relationship maintenance, and affect social capital processes. In this paper, we study a corpus of public status updates posted to Facebook (N=7,466) in order to identify the pattern of responses to status updates that attempt to mobilize resources from the poster's Facebook network. Findings suggest that mobilization requests are treated differently than other kinds of posts; posts that attempt to mobilize help receive more comments than non-mobilization attempts. Additionally, responses occur more quickly and are shaped by the type of support requested (e.g., a recommendation vs. a favor). These findings help us better understand the role of help-seeking behaviors in the social capital conversion process as it unfolds via social media.

Online dating systems play a prominent role in the social lives of millions of their users, but little research has considered how users perceive one another through their personal profiles. We examined how users perceive attractiveness in online dating profiles, which provide their first exposure to a potential partner. Participants rated whole profiles and profile components on such qualities as how attractive, extraverted, and genuine and trustworthy they appeared. As past research in the psychology of attraction would suggest, the attractiveness and other qualities of the photograph were the strongest predictors of whole profile attractiveness, but they were not alone: the free-text component also played an important role in predicting overall attractiveness. In turn, numerous other qualities predicted the attractiveness ratings of photos and free-text components, albeit in different ways for men and women. The fixed-choice elements of a profile, however, were unrelated to attractiveness. Author Keywords Online personals, attraction, computer-mediated

In this paper we describe an evaluation of behavioral descriptors generated from an analysis of a large collection of Usenet newsgroup messages. The metrics describe aspects of newsgroup authors' behavior over time; such information can aid in filtering, sorting, and recommending content from public discussion spaces like newsgroups. To assess the value of a variety of these behavioral descriptors, we compared 22 participants' subjective evaluations of authors whose messages they read to behavioral metrics describing the same authors. We found that many metrics, particularly the longevity and frequency of participation, the number of newsgroups to which authors contribute messages, and the amount they contribute to each thread, correlate highly with readers' subjective evaluations of the authors

An appropriately designed interface to persistent, threaded conversations could reinforce socially beneficial behavior by prominently featuring how frequently and to what degree each user exhibits such behaviors. Based on the data generated by the Netscan data-mining project [9], we have developed a set of tools for illustrating the structure of discussion threads like those found in Usenet newsgroups and the patterns of participation within the discussions. We describe the benefits and challenges of integrating these tools into a multi-faceted dashboard for navigating and reading discussions in social cyberspaces like Usenet and related interaction media. Visualizations of the structure of online discussions have applications for research into the sociology of online groups as well as possible interface designs for their members.