I have just finished getting my new project to the "usable" stage, so I thought I'd go ahead and let you know about it. It's an academic paper sharing/tagging site (slightly similar to
del.icio.us, but for papers). I guess it's kind of a "mash-up" since it uses at least 3 different sites' APIs (Google, CiteSeer, and Citidel). Take a look and tell me what you think!