I don't like that IPs are sometimes kept indefinitely. To prevent abuse, it would probably be sufficient to keep them for ~6 months. But keeping these logs long-term is extremely useful for account recoveries. I've been thinking about this issue, and I think that in the future I might let users opt out of long-term IP logging if they have a public key registered in a (currently-not-existing) public-key-registration system. Though, again, even then you should model this site and all sites as keeping complete logs.