Pixrat is basically del.icio.us for photos. I don't say that disparragingly, though--Pixrat works as advertised and will definitely be useful for some people. By clicking on the Pixrat bookmarklet when viewing a page with a photo on it you can give the photo a description and tags, then later you can browse your boomarked photos with handy thumbnails, optionally searching by tag. You can also, of course, browse everyone else's photos or view the most popular recent photos. Pixrat does lack a few of del.icio.us' more powerful features like tag intersections and RSS feeds, but those issues aside, I can see Pixrat as being very useful people who keep track of a lot of stock photos, for example, at a number of different sites.