Google have just recently ‘re-iterated' the fact that they will ‘penalising' companies that buy links on the Internet in the hope to manipulate their rankings in the Search Engine Results Pages (SERPs). This has been known for a while in the world of search engine optimisation marketing and has been hotly debated amongst the top search engine optimisation specialists for the last two years.
Google's definition of what a paid link is not one where you pay a guy to submit your site to 500 SEO friendly directories, neither is it a 'quality link' purchased in a Directory like Joe Ant, Yahoo or Green Corner; these directories ensure anchor text and relevancy. However, a forum poster that offers to sell you links based on a toolbar PageRank is a paid link, high PageRank websites that feature a sponsored links section and the links within are defined as paid links. Even deep links and paid directory submissions are considered as ‘paid links' by Google; as Matt Cutts himself puts it “paid links that flow PageRank and attempt to game Google's rankings.”.
Matt Cutts works for the quality group in Google, specializing in any search engine optimisation issues. He is especially well known in the search engine optimisation community for enforcing the Google Webmaster Guidelines and even more so for cracking down on link spam, so perhaps all of us in the search engine optimisation community should take note of what he says?
People are still in a large debate to whether they can be moderated at all and if the negatives associated with the ‘Google Slap' are as harmful as made out by Google. The main point that is bought up is how Google are going to detect bought links; if direct contact is made between two webmasters via E-mail or telephone and money is sent via post there is no way Google could know.
This point is valid, until somebody doesn't like the prices, declines to buy an ad on your site and then turns around and reports you to Google for selling links. Google's reporting system for letting them know who is buying and selling links is well known in the SEO community and I suspect they take this very seriously.
As well as reporting, Google has other methods for detection. For example, if the user you have just sold links to has bought links on other sites that have got caught, this will end up getting reflected back on you. It might be that they get reported for other negative actions or their competitors report them, thus coming back to you. Google, which is a multi-billion dollar company, with more advanced technology than most of us have even heard of, is not going to be easily fooled.
The long and short of it is, whatever you do, you do at your own risk. Google has its rules and regulations and does not appreciate people breaking these rules; considering Google holds the power, is it worth paying the price?