TABLE 1.
Characteristics of and Web Site Utilization Data for Participants in the QuitNet Online Social Network for Smoking Cessation: March 1, 2007–April 30, 2007
| Weakly Connected Corea (n = 7569) | Strongly Connected Coreb (n = 4407) | Densely Connected Corec (n = 554) | Key Playersd (n = 50) | Newcomerse (n = 792) | Integratorsf (n = 756) | |
| Age, y, mean (SD) | 42.3 (11.2) | 43.8*** (11.1) | 46.3*** (10.2) | 49.3*** (10.7) | 38.9*** (11.3) | 45.1*** (10.4) |
| Female, % | 72.0 | 72.5 | 78.5*** | 80.0 | 74.0 | 76.6** |
| Smoking at baseline, % | 65.7 | 64.7* | 66.7 | 77.6 | 100.0*** | 60.6** |
| Smoking at last observation point, % | 44.3 | 39.4*** | 35.1*** | 28.0* | 85.5*** | 29.3*** |
| Abstinent for entire study period, % | 45.5 | 54.7*** | 61.7*** | 64.0** | 1.0*** | 64.1*** |
| Median no. d since registration (interquartile range) | 175 (54–640) | 351*** (96–785) | 432*** (162–797) | 546*** (187–865) | 47*** (41–54) | 269*** (95–750) |
| Time since registration, % | ||||||
| < 3 mo | 36.3 | 23.4 | 14.4 | 6.0 | 100.0 | 23.0 |
| 3 mo to 1 y | 24.4 | 27.6 | 28.0 | 24.0 | … | 32.8 |
| > 1 y | 39.3 | 48.9 | 57.6 | 70.0 | … | 44.2 |
| Logins, median no. (interquartile range) | 8 (3–32) | 17*** (5–62) | 127.5*** (41–249) | 268*** (164–416) | 5*** (1–15) | 96*** (31–210) |
| Forum posts, median no. (interquartile range) | 0 (0–3) | 1*** (0–7) | 11*** (0–82) | 135*** (17–456) | 0** (0–2) | 27*** (6–110) |
| Forum partners, median no. (interquartile range) | 1 (0–9) | 3*** (0–21) | 50*** (14–102) | 143*** (50–305) | 0*** (0–5) | 53*** (17–110) |
| Forum partners who reciprocated, % | 31.4 | 42.6*** | 84.1*** | 92.0*** | 26.0*** | 87.8*** |
| Buddies set, median no. (interquartile range) | 0 (0–2) | 1*** (0–4) | 13*** (7–23) | 19*** (6–48) | 0*** (0–0) | 3*** (0–10) |
| Buddies who reciprocated, % | 23.3 | 40.0*** | 84.7*** | 86.0*** | 9.7*** | 52.6*** |
| Chat partners, median no. (interquartile range) | 0 (0–1) | 0*** (0–1) | 0* (0–2) | 0** (0–4) | 0*** (0–2) | 0*** (0–2) |
| QMail messages, median no. (interquartile range) | ||||||
| Sent | 0 (0–3) | 1*** (0–8) | 39*** (8–135) | 209*** (78–633) | 0*** (0–1) | 14*** (2–57) |
| Received | 1 (1–4) | 2*** (1–10) | 46*** (11–132) | 169*** (63–320) | 2** (1–3) | 16*** (3–60) |
| QMail partners | ||||||
| People sent to, median no. (interquartile range) | 1 (1–3) | 2*** (1–5) | 12*** (5–25) | 57*** (32–114) | 1*** (1–3) | 7*** (3–19) |
| People who reciprocated, % | 41.5 | 58.5*** | 91.7*** | 98.0*** | 30.9*** | 83.5*** |
| Club memberships, median no. (SD) | 0.6 (2.7) | 0.8*** (3.5) | 2.1*** (6.4) | 3.6*** (5.9) | 0.6 (1.6) | 1.8*** (5.5) |
Note. Actor = an individual with connections to others in the network; QMail = private e-mail messages on the QuitNet network. The weakly connected core minus subgroup N (strongly connected core or densely connected core) served as comparison group for all subsequent subgroups. Ellipses indicate not applicable (these individuals were excluded by definition of the group).
Participants who completed 1 or more of the following actions during the observation period: (1) exchanged an internal message with another participant, (2) posted a message in the online forums, or (3) added, or was added by, another QuitNet participant to a buddy list.
Limited to participants connected by buddy nominations and observed communications.
Limited to participants connected by symmetric buddy nominations plus a minimum of 5 communications with at least 1 buddy.
Actors with high levels of connection to the entire community.
New registrants to the site in the first 4 weeks of the study.
Participants who were registered on the site before the study began and who initiated and formed ties (through Qmail or forum message) with newcomers.
*P < .05; **P > .01; ***P < .001.