From an Associated Press article:
Twelve administrators of the website Formspring.me, including CEO Mark Baxter were arrested on Monday for data phishing and misleading the public, when the site was revealed to be a “social experiment,” which will culminate in the automatic revealing of users’ private data on April 1, 2010.
Update: seems like this is a hoax…

Pretty sure that’s just a rumor since I can’t find the information anywhere else on the internet except a personal site of someone.
Interesting, looks like you’re right…