That would require a bit more infrastructure on Gravatar's part (a UI for registering a site), and would significantly slow its adoption because site owners wou

That would require a bit more infrastructure on Gravatar's part (a UI for registering a site), and would significantly slow its adoption because site owners would have to go register their site before they could generate gravatar URLs. I used Gravatar for my site because it was so easy to implement, and I probably wouldn't have bothered if it was an annoying process like this.