Paid links are an incredibly gray area. What exactly is a paid link? How can Google figure out what is paid and what isn't? Where does Google draw the line? Google's Matt Cutts dives into the topic of paid links in a new webmaster help video.
Conversion rate optimization is one of the most effective ways to grow profits for a web business, whether it’s an SMB or an enterprise-level site. These tips will show you where to start, what to test, potential pitfalls to avoid, and more.
Some paid links are considered relatively evil, but others are much more widely accepted. Some may not like to admit it, but these strategies are all considered paid links – it all boils down to money (or items of value) being exchanged for a link.