Those of you buying link building services may find this interesting. I once setup a forum (long ago), now defunct and found it regularly spammed. http://forum.bingesite.com/ I cleaned it to nothing 0 users and 0 topics and posted one topic less than a month ago and you can see how quickly the spam has built up again. It is largely unmanaged and I clean it up routinely just for the fun of it. Not all link building services are alike. Some are basically doing just this sort of link posting. i find it rather interesting , to sit back and watch. Because everytime someone posts a link in this forum their site is most likely going into the Google heap of invisibility. What draws them to this forum, I do not know. Imagine if the forum was really backlinked to draw even more bots. All the bots would follow your site / blog to this forum and post within thereby listing themselves as spamvertised. Note that hosts (good ones) are routinely shutting down sites when a spamvertise claim is made against a site within their eco system. Also they are likely to be listed in most blocklists and if your site uses one of those services then you will be safe. Technically this forum is called a honey pot. It is a bait for trapping spammers. Or atleast I hope it is. If you were to browse around the sites that are posted (be careful though) you will find most if not all are redirected or closed of sites. If they are not they soon will be. You are also unlikely to ever find them in Google or any other good search providers. be careful who you pay for link building, forum posting, cheap traffic etc. Verify every link posted if you can.