Tara Hunt, Riya’s chief blogger, says on her personal blog that they’ve had a million photos uploaded just two days after launching. Riya leverages potent facial and text recognition technology with an intelligent interface to help people make sense of the thousands of untitled and untagged photos that are building up on their hard drives (and on the web).

The process starts with registration and choosing a privacy setting on your pictures. You then download a client application that uploads photos you choose to include in Riya. The actual uploading takes a while - about 4 hours for each GB of photos. Instead of waiting around, Riya will email you when the process is complete.

Riya also recognizes text in photos, and lets you select any area of a photo and tag that as well. For instance, you could select just the Eiffel Tower in a photo and tag it as such. It’s an easy step to allow friends to also tag and search your photos (if you choose), and even allow full public search.

Linking these two features - massively automated tagging of everything in photos, with search, is compelling to say the least. The folks at Riya call it “tag locally, search globally”.

As people use it to tag photos, Riya will create a database of unique attributes of people. Once enough people start using the service, Riya will be able to auto-tag people’s names with less and less training by the user.

Riya plans on having a destination site that will be free, and will OEM their service to other photo services.