is this a risky practice?

[boobird]

carcasher.com ranks in the top 10 for "used cars". The backwards links are mostly crap. the site holds seo contests. Is there a chance that google can crush this site? how does google differentiate between crap and good backlinks?


http://www.google.com/search?hl=en&q=link%3Ahttp%3A%2F%2Fwww.carcasher.com&btnG=Search