Introduction: Little is known about how group cohesion develops in online support group communities. Previous research suggests that message content, self-disclosure, and emotional expression may be central to this process. The purpose of this study was to identify linguistic and qualitative characteristics of participants' messages that predict how other participants respond in an asynchronous discussion board for cancer-related distress. Method: 525 discussion board messages posted by 116 participants in the health-space.net trial were collected. Linguistic Inquiry and Word Count (2001) was used to identify linguistic markers of emotional expression and pronoun use. Message topics were identified using qualitative analysis. Logistic regression and chi-square analyses were used to evaluate whether linguistic characteristics and message topics predicted receiving a response from other survivors in the online group. Results: Messages were more likely to receive a reply if they had higher word count, OR = 0.30, p = 0.001, or fewer second person pronouns, OR = 0.923, p = 0.040. Messages were less likely to receive a reply if they evidenced high levels of positive emotion, OR = 0.94, p = 0.03. The most common message topics related to self-disclosure (51%), the group (38.5%), medical experiences (30.9%,), and experiences related to the website (30.1%). Several types of message topics were associated with greater likelihood of a reply: self-disclosure (p < 0.001), medical experiences (p = 0.01), relationship issues (p = 0.05), and introductory posts (p < 0.01). Implications: Informing participants how to introduce themselves to the group (i.e., detailed and self-focused messages discussing personal issues such as the effects of illness on life and relationships) could promote cohesion and enhance overall intervention engagement. [The dissertation citations contained here are published with the permission of ProQuest LLC. Further reproduction is prohibited without permission. Copies of dissertations may be obtained by Telephone (800) 1-800-521-0600. Web page: http://www.proquest.com/en-US/products/dissertations/individuals.shtml.]