It seems really obvious to me that there should be a "slogan" tag in addition to the "title" tag. Many, perhaps most, websites use their business name with a slogan in their title. Unfortunately, it means that every time I bookmark a site I seem to have to edit the properties to remove the stupid slogan from the bookmark name.
The behavior would be real simple: the slogan's text gets concatenated with the title's text to form the title in the browser window. But bookmarks and such would only use the title text.
This seems like a win-win situation for the web.