How Not To Build Links

“Links matter. No secret there. How much they matter, well…therein lies the secretive part of the equation. And as much as readers of this blog would love for me to slip up and say they account for N% of the equation, I won’t. The fact is, the actual value links apply varies based on other factors, so there is no solid number. Back when everyone was chasing “keyword density” as a ranking objective, everyone wanted to know what the magical percentage was. Same deal – it depended on a variety of factors. While keyword density has gone the way of the dodo, links continue to provide useful signals, despite the obvious spamming that happens. So let’s take a quick look at some ways to build links that you should avoid.”

http://www.bing.com/blogs/site_blogs/b/webmaster/archive/2013/09/06/how-not-to-build-links.aspx