It is disappointing there is no MSN toolbar for Firefox, because I quite like the features, however it is obvious why: Microsoft would prefer you to use only Microsoft products.
Microsoft is tinkering with a technology called Stuff I've Seen that will pull results from the Web along with one's own computer and its network. (Microsoft claims this won't make personal files viewable by the public.) Google's Internet Explorer toolbar tracks the sites users surf and relays the addresses back to headquarters.