fathom - 12:54 pm on Apr 12, 2012 (gmt 0)
We consider Guest Posting unnatural then too, right? So basically those people are in the same "unnatural" boat with the people buying links on #*$! sites, blog networks and text ads from ad sellers? Not sure who Google is going to have left to show in their results if they penalize everyone with "unnatural" links. Going to get real ugly in the serps.
Individual links are not detectable against the uproar of trillions of links... but the sniff test... was the posts' link for "advertising" or "editorializing"?
If the post is purely for advertising then the link should have rel="nofollow". Obviously, if you have a problem with rel="nofollow" in your post's link we know the reason for the link wasn't editorializing.
Do I believe that Google is that granular on individual links... no, not a chance... but if you have say 500 guest posts and all have the same link anchor pointing to the same page... that could be easily seen as "unnatural".