Do you think that google apply penalties in this situations 1. If you got a high value of backlinks from free web directories !? 2. If you got the same anchor texts over and over again !? 3. If you website appeared in the buy/sell links area of several online websites as digitalpoint,sitepoint,linkmarket
Sure... but I think the *most common* is #2. #3 would really suck and if that were the case you could easily start fake threads and list the URL's of your competitors and sink their SERPS... unlikely. #1 doesn't even have to be directories I suspect if you get a high number of backlinks from just one type of sites then your site doesn't look natural. If you take a look at some of the top ranked sites in the Google SERPS they have backlinks from everywhere. -directories -blogs -related websites -articles -social networking links Hope that helps!