At the moment, there is no difference between: https://stackoverflow.com/users/27290/margaret and http://facebook.stackoverflow.com/users/27290/margaret
Surely it would be a good idea to filter the mini-site's profile to only the same tags as the mini-site allows? I'm primarily talking about the questions shown; I am not a Facebook dev, so I was surprised to see questions until I realised they were the VBA questions I posted on the main site.
Possibly also having a way of showing "My reputation in this particular subtopic" - the current reputation displayed is for StackOverflow overall, even though the
/users page displays only reputation garnered from those specific tags. Yes, we still should show the user's overall site rep as well, but maybe the bigger number should be "My value 'round here"?