Meet the 24 year old founders winning the battle against junk mail

I've seen a lot of tweets and Facebook posts about Unroll.me.

...because it appears that they exploit social autosharing to both services, as I see canned "I just subscribed to Unroll.me!" messages all the time. (see: https://twitter.com/search?f=realtime&q=unroll.me&src=typd and note the referral indicators)

That particular tactic is enough to turn me off of a service, no matter how useful it is.

Does anyone know what their business model is? I assume one would pay for a subscription, but I couldn't see pricing information on their website.