This has been happening for a couple weeks now and I've gotten enough email about it to provide a front-page explanation: points have started to expire, which they do after a year. This is not functionality I put in intentionally but I might keep it around since it seems to make sense. But that's what's happening. If you get a snarky email about losing super powers but haven't done anything to warrant it, that's what's going on.
A comment revamp is coming and I don't want to touch anything on the site until that's up and going, so please bear with us.