More software someone should write: Cookieshare (or Cookiejar, or some play on "cookie jar" that reflects its network nature), a P2P service for automatically sharing site login cookies. Works as an HTTP proxy. Lets you choose which sites you don't have (or want) cookies for; pulls a cookie from the network when you request a site in your list you don't have a cookie for, and pushes (or offers) a cookie to the network when you receive one from a site in your list.
