there is a free online user widget in addons page :
Online User Count by Ali Sayahiyan @ Question2Answer Farsi. Shows a list of users who are currently online.
Welcome to the Q&A site for Question2Answer.
If you have a question about Q2A, please ask in English.
To report a bug, please create a new issue on Github or ask a question here with the bug tag.
If you just want to try Q2A, please use the demo site.