Thinking about Blog Contests

Thinking about Thursday


Even before the grand announcement from Facebook and Twitter that they are banning contests, I had been thinking about blog contest and their effectiveness.

Ashley March has a great post that lays out the new Facebook rules in plain English. Grace Burrows also had some terrific points about why these new terms may not be as catastrophic as some authors believe.

But, I have been thinking about blog contests in a different way. Basically, what is the purpose and are they effective? 

If you follow/leave a comment on a blog, "like" a page or retweet a link for the purposes of entering a contest, when the contest is over, do you become an active member of that page or is it just another name on your Google reader?

If you have held a contest on your blog, did you find it significantly increased your traffic in the long-term or only for the duration of the contest? 
What prizes do blog readers prefer? Free books? Critiques? Small gifts? 

Please understand, I am not knocking contests. I am genuinely curious if the contests are an effective tool ?
What do you think?