I had heard that Gravatar 2.0 had been released, but hadn’t really paid much attention. Today, while doing a little housekeeping around the site, I noticed that none of my gravatars were showing up. After doing a little investigating, I realized it had to do with caching, among other things. First thing I did was dump the cache on my gravatars folder in wp-content. Second, I logged into the gravatar site, and re-associated my gravatar with my email that I use for that account. Still no gravatars, mine, or anyone else’s.
So I looked at the settings on Skippy’s gravatar plugin (which I like as I can set a local gravatar, vs using a default one from the original site), it was set to use caching. I turned that setting off, and voilá, gravatars are showing back up. Hopefully that could help someone else (though, from reading a few blogs, and the comments on the main site, there’s no guarantees the main site will be with fail).