Yesterday we ran a poll on how risky is link buying. Well, the last thing you want is me writing about your site when it sells links. :) Unfortunately, I found an interesting *public* thread at Google Webmaster Help about a big time web site, Yell.com allegedly selling links.
The person who started the thread clearly wanted Google to take notice and he leaded to an example of a page with "sponsored listings" that are links without a nofollow. Take a look for yourself.
If you view the source code, you clearly see that Yell.com understands how the nofollow attribute works. They have it on their printer friendly links and links where they do not want to pass or dilute their PageRank (which we know doesn't work too well anyway). The links doesn't go through any redirect, as far as I can see. So it does seem to be passing PageRank.
But is this a paid link?
It seems like even the free listings are passing PageRank. It also seems like a web directory like approach that can be equated to the Yahoo Directory or Open Directory Project. Kevin in the forums said he doesn't think this is a true paid link, he explained:
When you upgrade a free standard listing by buying a paid listing in Yell you are not buying a link. Having a link to your website on your paid advert is an optional extra - it is not what you are paying for. What you are paying for is extra pominence in Yells directory. You do not pay any extra if you have a link to your site. therefore you are not buying links when you buy a listing in Yell. If you buy a heavyweight listing at Yell and do not have a web site you don't get a discount on the fee because you don't have a link. Therefore you are not buying pagerank or paying to influence your SERP, you are doing nothing except to boost your Yell listing within Yell itself.
Forum discussion at Google Webmaster Help.