We do have a favorites plugin that is sort of in an incubation stage right now, I'm not sure if it allows for favorites on other sites besides Clearspace. Favorites is something that comes up a lot and so it will eventually be part of Clearspace somehow, but it won't be part of 1.7.
Just for the sake of the conversation, are you looking to replace browser bookmarks? or something like del.icio.us for internal usage? is the social part of favorites big or is it more just a convenience thing for users?
It would be more of a convenience thing within our site for registered members. Based on a certain topic of information, a member could bookmark a page. We want the user experience to have one place for all bookmarks on the site, including the community section.