Martin Riya is a photo sharing and search site that will tag and index your photos automatically using intelligent recognition (there's the Riya blog). Riya recognizes faces in photos, you tag them - it sorts them. There's lots of comment here. You might say this is the ultimate in social networking. It’s in Beta at the moment, but looks pretty impressive. I’m wondering whether this feature would make me abandon Flickr. I think not - after all I was frustrated by the difficulty of getting category-tagging on Blogger, but now it’s here…and all I need is the time to transfer my blog.