Kevin Drum, the fine lefty political blogger whose more famous blogging institution is his introduction of cat-blogging, recently got a new cat after his old one, Jasmine, passed away. His is a two-cat household, and anyone who's ever introduced a new cat into a household that already had a cat will recognize the way Kevin has been guaging Inkblot's (the established cat) reception to Domino (the new cat).
When we brought Lester and Julio in, it was four or five days before Comet even came out from under our bed. Now she plays with Lester, while still despising Julio. (Which is probably because Julio, being really dumb and all, keeps trying to do the dirty with her.)