You maintain a blog at, say, livejournal.com (but this can be anything) and you stay logged in there usually. You go to leave a comment at someblog.com (perhaps it's Movable Type, or Wordpress, or DeadJournal, ...) and you don't have an account there, s
OpenID is a lightweight, decentralized identity system that has been gaining prominence. I expect this upcoming year to be a big year for OpenID -- and not just because of the Google trend chart with the recent uptake in search query share.