I’ve already tried to make myself unpopular with the I support nofollow campaign (which is currently supported by only one blogger; me) and my reasons why I support nofollow.
My blog-sense is at it again. I just know that by pointing out selling links could be risky I suspect I'll attract even more frowns.
Right now link selling seems to be risk free. Google, via Matt Cutts, have made it clear that link sellers loose their ability to pass PageRank on. They loose their ability to vote for the sites that they link to. The link buyers cannot see that and so keep buying links from the caught link sellers.
But what if Google tweaked things so that link buyers could see which sites had been caught selling links? What if the PageRank bar in the toolbar turned from green to black for link sellers? The link seller would find themselves with a black mark. Quite literally.
It's hard to gauge whether Google would do something like that. Right now, as long as Google is confident that link selling is not corrupting the search results too much then the search engine will be happy that its defences are strong enough. After all, Google doesn't mind if people pour money into useless bought links.
Google certainly seems keen to avoid removing quality sites which just happen to sell links from its own search results. Many high profile sites sell links. The invisible penality which prevents these sites from passing PageRank on does not prevent them from gaining PageRank or even gaining high search positions.
A public black mark approach wouldn't disrupt that desire either. Quality sites which earned a little cash through link selling would continue to rank well. The only change would be that those who knew where to look would know the site had been caught. One risk could be on the legal front. There may be legal issues in calling someone a link seller if they're not. False positives are not a problem in the current system because no one knows they are there.
Would a public black mark encourage less people to sell links? I think it would. Some people simply would not want to risk entering Google's bad books. If the black mark became a significant stigma or shame then even more webmasters would shy a way from selling links.
Ironically, I suspect a public black mark for link selling would encourage more webmasters to use 'nofollow'. In order to avoid the risks of false positives and being wrongly labelled as a link seller then more webmasters and bloggers would be far more liberal with their application of 'nofollow'.
There may seem to be no real risk in selling links today. Tomorrow black marks might start to name and shame sites around the web.