Data to be collected. Assessment data will be obtained at: Baseline, post-intervention, and at 3- and 6-month post- intervention follow-ups (or comparable time-points for controls). If results are promising, longer follow-ups may be incorporated into future research projects that allow for longer evaluation periods than the Phase II grant mechanism. Participants in the experimental arm will be asked to complete the post-intervention assessment immediately after they complete all modules. Consistent with an intent-to-treat analysis, participants who do not complete all modules within a 4-week period will still be provided with the opportunity to complete a post- intervention assessment at 4-weeks post-group assignment and to complete follow-ups. The investigators plan to collect the following data in addition to the data captured by the primary and secondary outcome measures (described in that section): basic demographic information; other substance use information; feedback survey data (post-intervention time point only); assessment of usage data (e.g., number of times each module is accessed, duration of usage of modules, time to quiz mastery within modules, and extent of module completion). Participants will complete all assessments online (in a secure manner; see protection against risk).