Handling user abuse in rails

Question

I've been working on a web app that could be prone to user abuse, especially spam comments/accounts. I know that RECAPTCHA will take care of bots as far as fake users are concerned, but it won't do anything for those users who create an account and somehow put their spam comments on autopilot (like I've seen on twitter countless times).

The solution that I've thought up is to enable any user to flag another user and then have a list of flagged users (boolean attribute) come up on a users index action only accessible by the admin. Then the users that have been flagged can become candidates for banning(another boolean attribute) or unflagging. Banned users will still be able to access the site but will have greatly reduced privileges. For certain reasons, I don't want to delete users entirely.

However, when I thought of it, I realized that going through a list of flagged users to decide which ones should be banned or unflagged could be potentially very time consuming for an admin. Short of hiring someone to do the unflagging/banning of users, is there a more automated and elegant way to go about this?

Answer 1

Before "Web 2.0", web sites were moderated by administrators. Now, the goal is to get communities to moderate themselves. StackOverflow itself is a fantastic case study. The reputation system enables users to take on more "administrative" tasks as they prove themselves trustworthy. If you're allowing users to flag each other, you're already on this path. As for the details of the system (who can flag, unflag, and ban), I'd say you should look at various successful online communities (like StackOverflow) to see how they work, and how successful they are. In the end it will probably take some trial and error, since all communities differ.

If you want to write some code, you might create a script that looks for usage patterns typical of spammers (eg, same comment posted on multiple pages), though I think the goal should be to grow a community that does this for you. This may be more about planning than programming.

Answer 2

I would create a table named abuses, containing both the reported user and the one that filed the report. Instead of the flagged boolean field, I suggest having a counter cache column such as "abuse_count". When this column reaches a predefined value, you could automatically "ban" the users.

Answer 3

Some sophisticated spammers are happy to spend their time breaking your captcha if they feel that the reward is high enough. You should also consider looking at a spam server such as akismet for which there's a great rails plugin (http://github.com/jfrench/rakismet).

There are other alternatives such as defensio (http://defensio.com/downloads/rails/) as well as a gem that I found once which worked pretty well at detecting common blog spam, but I can't for the life of me find it any more.