At the moment, as Hannele observes,
* by itself is not a very useful filter to use on favorites (and I may even block it). I'm thinking in my head of various ways of implementing it, but I can't help thinking that it is simpler just to use the existing multi-tag functionality, for example:
(which is readily bookmarked etc)
We could perhaps make it easier to get to just your favorites, for example at
/questions/favorite. However, I don't think that what we're discussing here should be implemented by hacking the
* as a filter - if anything, we should remove the ability to enter
* as a favorite / ignored tag.