Tallon - 10:05 pm on Sep 29, 2010 (gmt 0)
Can't that be abused too? Why not just tell a bunch of people to link to your site under a false pretense of say some kind of reward? Like the old tricky approach of "pass this email on (link to this site) to 20 friends and Bill Gates will pay you $$$$". Or how about actual paid links from social site users? I can hear the gears spinning already on "how can we beat this"? Word of mouth is great until it becomes PAID word of mouth, and how can Godzilla determine that?
Watch the "mommy" and "food" blogger niches, you can "win" everything from kitchenaids, shoes, clothing, etc., just for retweeting, subscribing or linking to a twitter profile or blog post. Same with facebook "likes", blog posts, leaving blog comments (and one contest can generate hundreds, even thousands, of comments and links). That's been happening for at least 3 years now so I HOPE google is accounting for this incentivized social media "buzz".
Edit: adding subscription numbers are inflated too since if you subscribe to a blog or a twitter profile or a facebook profile, it counts as another "entry" into the contest.