I believe a useful feature on the expanded usercard would be the time a user was "last seen". The time a user was "last seen" can already be found on their profile.
Currently the expanded usercard can look like:
when a user has not provided a link to their website.
And as you can see, there is a void below the user's location. Why not fill it with something useful:
My feature request is actually slightly more general: regardless of a provided website or not, simply include the "last seen" info somewhere on the expanded usercard.