Yahoo and MSN have been much quieter on the topic. They've certainly indicated at industry conferences that they don't want publishers to buy links for the purpose of affecting their rankings in the search engines, but less has been said about how they act on that policy.
During a recent interview with Yahoo's Priyank Garg, I got a much clearer sense of how Yahoo's policy on paid links differs from Google's. Let's take a look!
Google Policy on Paid Links
Here's my brief summary of the policy: Offering compensation for a text link ad is a normal part of the Web economy. However, doing so for the purpose of influencing PageRank, or your rankings, is against their guidelines.
It's also well known that Google provides a way for users to report paid links that they see to Google. While according to a survey by Barry Schwartz, less than a third of SEOs report paid links, this is a relatively important source of data to Google on the topic.
Yahoo Policy on Paid Links
Here's a summary of Yahoo's policy on paid links, using an excerpt from my interview with Garg:
"If a paid link is not valuable to the users, we will not want to give it value. Our algorithms are being organized for detecting value to users. We feel most of the time that paid links are less valuable to users than organic links. But that's not black and white, it is always a continuum. Yahoo continues to focus on the element of recognizing links that are valuable to users, building mechanisms in our algorithms that attenuate the signal and capture as much value from that link in context, rather than worrying about it being paid or unpaid."
One thing both policies have in common is that both search engines are concerned about how paid links impact their rankings. However, in Google's case, the key concept (or goal) is that all paid links should have no impact on search rankings.
This is pretty difficult to execute against, and it's what has led to Google offering a paid links reporting mechanism -- to get help. It has also led to Cutts suggestion that publishers that sell text links mark their links with the nofollow attribute.
Yahoo appears to be taking a different route. As I read the comments by Garg, it seems that they focus more on the end user value of a link, whether it's paid or not. To read between the lines a little bit, end user value is most likely being measured by the relevance and context of a link.
This saves Yahoo from fighting a difficult battle, a battle that has led some to say that there's an arms race between Google and spammers. Certainly if this battle is inherently unwinnable, the Yahoo approach may be a pragmatic one.
For example, Yahoo doesn't have the burden of being called out in posts like this one by Michael Gray, which accuses Google of having a double standard.
Gray's post outlines a scenario in which a PR firm wines and dines a bunch of high profile A-list bloggers with an all expense paid weekend getaway, and then asks them "if they had a good time please write about it on their blog and post some pictures to flickr."
Many have cried out for Google to recognize paid links as a part of the Web environment, and to develop ranking algorithms that are less subject to being affected by them. Of course, if this was simple to do, the search engines would have moved on from links as a major ranking factor a long time ago. Don't expect it to happen any time soon.