What do the Facebook applications developers get out of my participation? ?

[Wondering in Indiana]

I can send snowmen, sheep, hugs, etc. What do the developers/companies gain from my participation? And how can they use my data?

Thanks!

[Mr Kite]

1. Some applications make money directly, by displaying adverts. Scrabulous was making $25,000 a month through advertising before it was shut down [1].

2. A lot of applications provide advertising for one particular product or service. For instance Sony paid for a Bob Dylan application to promote sales of Bob Dylan's albums[2]. The "Where I've Been" application was bought for $3 million by an online travel company[3].

3. A lot of smaller apps are created by bored students just for the fun of it. It only takes a day or two to write an app that allows you to throw snowmen at each other, and unless you have a very large number of users bandwidth costs are negligible. I was bored one day and wrote a Facebook app which let people add extra information to their profile, but it had been done by a thousand other apps already and had no users, so I deleted it.

4. How they can use your data is defined
a) in their Terms of Use[4]
b) in the application guidelines[5]

They do not get access to your contact details (address, email address, phone number, etc).[4] They also obviously don't get access to your photos, wall posts, etc.

There are various rules about applications not being allowed to do anything illegal, lie to you, spam you, etc [5], but of course if someone wants to do something illegal they will do so anyway.