"social bookmarking site" is a good way to describe it.
It's also called a link blog.
Here's mine:
drmomentum's bookmarks on del.icio.us
I use it to keep track of links for my own purposes (like for shotgun posts and my own reference). But like Flickr, there's a social aspect to it because other people can see your links. It's a little less social than Flickr, because you can't comment on links.
So it's really more a place to keep track of and share web page links.