After 7+ years, I’ve seen it all in blog comments. Genuine people responding, asking and sharing in ways that inspire streams of comment responses and even blog posts elsewhere on the web.
I’ve also seen far too many bots that automatically find blog posts that are of a certain age, written on a certain keyword topic and that have follow vs. nofollow links. Once found (automatically using software) they scrape parts of previous comments to create a new one with embedded links to their Viagra SEO New Delhi Insurance Leads spam site. Bleh.
Then there are the benign “good job [insert blogger name here] comments or those that have been translated into another language and back into English. Here’s another good one: comments from reputable people from reputable companies that insist on leaving their full email signature in the comment. One link isn’t enough, they must have two or three or more. Greedy.