BuddyPress.org

Here’s a tweaked version of @dnxpert ‘s code that works on WPMU (don’t use this on single WP):
http://pastebin.com/Qfichf0t (paste in wp-content/plugins/bp-custom.php) (updated 06/12/2010 – 12:27am GMT)

The positives with my code is you can use the favorite / unfavorite code from bp-default/activity/entry.php verbatim without duplicating the favorite functions.

For the devs: If anyone knows a way around using the switch_to_blog() function, let me know; I used switch_to_blog() because of the generated nonce code.