I had been wondering why my Gravatar images haven't been showing up for a while in the comments on my blog. I had thought that it was because Gravatar is moving servers - their homepage currently says:
In order to handle the rapidly increasing load, I've had to experiment with a variety of server architectures. I ask for your patience during the coming weeks as I test out a few setups. The new and improved, vastly more scalable solution, will serve gravatars expediently and reliably.
But when I was over at Jon Hicks blog today, I noticed that his gravatars were working fine.
The problem was that my Hash had uppercase characters in it (this is because I'm using ColdFusion and its Hash function returns upper case Hex characters. The new gravatar requires a lowercase hash code.
It's a pretty simple fix, just wrap the Hash call with LCase()
LCase(Hash(comment.email))