Matt Cutts recently uploaded a new webmasters video explaining about what is a paid link? Google has been very cautious in detecting paid links. This video discusses certain criteria which Google uses while determining whether a particular link is paid.
Matt clearly says, sometimes people don’t pay money directly in return for a link but instead they offer beer, Pizza or a free dinner! The thing that matters is your intent because that remains the same. If your intent is buying links then Google will quickly catch you!
Over to the video-
Also See:
Paid Links are a Violation of Google Guidelines
Identify Which Links are Paid
Google Disavow Links Tool
Google Reminds of Taking Action Against Sites That Sell Page Rank
How to Design Seo Friendly Web Page
Links from Article Marketing Sites
No Follow Vs Do Follow
