The document action "Add to favorites" is outdated and should be updated with more advanced bookmarking capabilities.

From limi.net:

"Early versions of Plone had the notion of “Favorites” — a way to bookmark content that was useful to you in a particular Plone site. This implementation unfortunately was very basic, so it didn’t get much use among the power users, and it never got much maintenance or improvement. Later on, it was dropped, since nobody was willing to maintain it, and it really didn’t do much anyway.

... I’d like us to bring back new, improved favorite support in Plone. Some ideas for cool things we can do with these:

* Use Gmail’s “Star” concept to make an efficient, simple UI to mark content for later retrieval.

* Dashboard portlets with your favorites.

* Let the number of "stars" on a document imply things about its ranking in search results. As del.icio.us shows, this is a great indicator of popularity.

* Introduce the "follow" concept from Twitter to Plone — “star” users like content — and be able to follow their updates and additions in the site. Dashboard portlet to list these, with RSS support.

* The favorite marker can mark content to be available offline via plugins like Google Gears"