HN user
Excellent find. You can even access around 25 photos from Mark Zuckerberg's profile.
http://imgur.com/a/PrLrB (ps: what a nice photo of them on halloween. very generous too I can see!)
Haha yes, you're certainly right. A start-up offering this service would have to do it on some sort of monthly subscription, say $20-30 a month. Though yes, I agree that this doesn't have nearly as much potential as groupon.
Do you guys have someone in house to run your groupons? This seems like a good service for a start up to offer.