Bots across the internet cause a lot of spam for website owners and organizations. A few common spam bots include comment spam and referrer spam.
- Referer Spam also known as 'log spam' or 'referer bombing' is a kind of spamdexing (spamming aimed at search engines). [From Wiki]
- Comment Spam are typically characterized as irrelevant messages posted by spammers as comments on forums and blogs.