We have recently rolled out a web content filter. I have noticed on many users www.gravatar.com even though these users are not going to this site, nor have any program loaded that would connect to this site.
Anybody know why this would be showing up. Some google searching has mentioned possibly being attached to emails.
However, at this point, it isn't making sense.
If your users are frequenting sites who use Gravatar as their avatar provider, like StackOverflow or ServerFault, you'll see a flurry of requests to gravatar.com.
Each question and answer generates a hit for the user profile back to gravatar.
Serverfault and Stackoverflow both use gravatar as their avatar providers.
Weblogs and sites they are reading uses plugins or query with APIs the gravatar.com website. For example, serverfault.com does.