When you go into your entry page on Stack Overflow, you get a list of your favorite tags on the right side, near the top. You can control which tags interest you and which ones don't.
I'd like an analogous mechanism in Stack Exchange. So if, for example, the "Database Administration" site is of interest to me, but the "Wine Making" site is not. I could see a list that shows me only the sites I've declared to be of interest to me. Maybe there could be a button marked "List all sites" to temporarily override this feature.
The location of this list could be the same as where the current list is.
Is such a feature of general interest?