Implement solution for spam prevention (Feature #636)

Please describe a bit more detailed what exactly you are currently missing. "Spam prevention" is a very generic term so please provide one or more actual use cases where an applied measure can prevent a spam vector. Most important would be the description of the spam vector.

In my personal experience, the most successful anti-spam measure so far was to require registration and email verification. Stuff that goes through is 99% human source and can't be prevented by automated anti-spam measures.

Hello,

to write a bot that automaticly register and check an POP3 account to visit the email verify link is a work of 15 minutes.

There're 2 areas where we need to prevent spam:

Registration¶

Implement an entry point for a verification provider. A default included one could be a captcha (e.g. ReCaptcha) or some Q&A module (answer "1 + 5 = ?", ), etc. This will prevent automatic registration. The email verification is in this case just a check that the email address is correct, so chili does not spam wrong users with ticket changes & co.

Creating/modifing content¶

As we all know, spammers sometimes register accounts by hand to work around captchas & co and add them to their "spam pool". Some time later these accounts will start to spam the issues, wiki, etc. Then its too late and we have a lot of work to delete this spam content and the users.

So here again, implement a entry point for a verification provider that will verify every change to content for non admins, non developers & co.

• a captcha
• a Q&A module
• some public useable content filter, e.g. Akismet & others (Mollom, AntiSpam Bee, Defensio and Typepad Antispam, etc)

I recommend to implement first a registration verify provider with an captcha (e.g. ReCaptcha) and/or a Q&A module.
This could be easily included into the chili core.