Doubt about spam? Clearing the real problem!

Question

I have seem repeated questions about spams... I would really appreciate if someone could clear my doubts (Problems these questions are being posed by me because I dont have enough experience with web systems):

1) Have people been having problems with spams because their Q&A sites allow non-registered users to post? Or are there also robots that are able to register?

2) Does captcha solve this problem? Does the problem persists with captcha?

3) Do these spans come from the same IP address or at least the same country? I never used but I know that it is possible to change the configuration of the server to avoid connections from given IP adresses.

4) Are there other possible solutions for non-english web sites? Or other ways to use captcha/recaptcha?

5) What are the standard practices to avoid spam in Q&A web sites?

Answer 1

1. Yes I think there are robots that have been registering.
2. The new captcha plugin in v1.7 has really helped and pretty much eliminated spam user accounts on my site.
3. A lot tends to come from India but it's from many countries and many different IPs.
4. There are some other spam plugins, check the plugins page or search the Q&A for them.
5. In addition to captchas, you can set posts by new users to require approval. I have it set so that you need the points equivalent of one upvote to no longer need approval.