I posted some thoughts on this topic some time ago here.
Here are some functionality that I thought such systems should provide. These are still at very high level and are evolving.
A digital photo album should provide following functionality:
• Add photos from
o Camera
o Phone
o Scanners
o Files, including e-mails
o Web sites
• Opinions
o Tags
o Annotations
o Comments (or blogging about photos)
• Finding photos
o Based on dates, places, people
 Combinations and variations of these
o Content
 Type of picture
 People
 Objects
 Concepts (peace, ambition, love, …)
 Similarity to other pictures
o Based on opinions
 Tags
 Popularity
 Interestingness
• Creating albums
o Events
o Topics
o Evolution of a theme
o Some social aspects
• Sharing photos
o Sending photos
o Monitoring availability
 From friends
 On topics
 Of specific types
• Managing photos
o Using groups to decide access levels for photos
 Private, groups, public
o Editing
o Deleting
o Reorganizing
We can build the detail functionality in all these aspects by looking at current systems and taking the best features from there.
Am I missing some obvious features?