The site is friendly on the eye and easy to use - very much "twitter-like." Still, there are many features missing such as a way to email photos to the site. But this site is in it's early stages so I image these features are right around the corner.
I'm not sure what the revenue model is for this site (much like twitter) but founder Ross Scrivener is an IT guy from England who love to take photos, so I imagine he just enjoys the site for his personal fulfilment in some way.
If you want to check out my progress, hop on over to http://365project.org/kylewsmith/365 and check it out!