Could we put the Username and member level above the Avatars. Everyone just seems like a picture now with their actual username so small (text is already small enough in chrome). Also increase the size of the username a bit.
Maybe you have a popup blocker or some kind of ad-blocking extension in Chrome.I use Google Chrome. So out of curiosity I switched over to Internet Explorer for a minute. The "hover preview" works great with Explorer. The no preview seems to be a Chrome issue.