Yeah, been happening a lot lately. Do those guys get paid per click or what? I just don't understand the point of it.
Its actually quite simple. Meta data for search results comes from combined search references inside of alternated text.
If you put 1 link inside of every thread, you will possibly get everyone at that forum to click on the link to your website that generates you money.
However, if you put on a whole mess of varied text with phrases that have a similar chain of text in alternating posts that link a reference to another URL that is referenced by 10 other links with the same data, and those reviews from the same 11 review anchors click onto a review that you can enable a search engine to take that information at exactly the right time it all gets referenced and cached, you can potentially raise desired search results within various search engines "for free."
If you provide this service to others, you typically get paid exponentially per line raise by relevant search result.
If you are line 8 for "best karaoke cd+g seller" and you are quoted a 1 dollar fold per raise, getting from 8 to 7 gets the botster 1 dollar, from 8 to 6 is 100. From 8 to 4 is 10000.