While I understand this is probably a very broad question, I'm trying to figure out exactly when adding a CAPTCHA becomes a necessary requirement for a site. I get the sense a lot of clients ask me to add CAPTCHAs to their sites and not all of them require it. However, I'm not always as eloquent on this topic as I should be.. Maybe it might help if a response contained answers to questions like these:
- What kinds of web sites should absolutely have CAPTCHAs?
- What kinds of web sites should consider using CAPTCHAs, but not necessarily always adopt them?
- What kinds of web site should go without CATCHAs, since there are very few incentives to having such a barrier?