Huh? Facebook becomes number 1 of photo sharing, not even they have thought thru how to monetize the whole thing.
Facebook Becomes Largest Online Photo Storage Site – MarketingVOX

What I learn from the case of facebook is the power of usability.  Myspace and flickr are the absolute first movers but the experience is far from satisfied.  No matter you talk about album, upload method(sophisticated? who cares!!), big storage or tag, these functions never come close to your life.  Facebook has captured the most important thing in photo sharing: multiple way communications.  Be more precise, it enable you comment on other’s photos at ease.  You know all photos that shared inside your circle, you know what other people comment your photo, you can even comment on your friend’s friends photos (this never happened in other community).  Sneak view is interesting enough to encourage users to share over facebook.