Removing the IP addesses came out of a backchannel discussion with SDAI-Tech1. We've publicly discussed it from different positions, but what ultimately swayed me was his sincerity in worrying about it. Whether or not I think there's a real risk is ultimately less important than the perceived risk. I want people comfortable here.

The thread highlights the two camps that I anticipated. The one use for IP addresses is tracking identity, and some people will miss instant access to the info. But it's still recorded on the server, and so if there's a real problem I can look up IP addresses.

At the moment old messages still contain IP addresses. I can delete all the old HTML message files, forcing regeneration without IP addresses; but I wanted to wait and see what reaction the move would get. Seems generally positive, so I'll purge the old messages this weekend.