BuddyPress

Since some plugins are adding stuffs into activity stream, so I guess adding a title would not be imposible. But, how? Can we work it out the similiar way as adding a metabox ?

On the backend, you’d need to experiment with adding some activity meta.

In BP 1.5, all the activity meta functions are available in bp-activity/bp-activity-functions.php:

http://buddypress.trac.wordpress.org/browser/tags/1.5/bp-activity/bp-activity-functions.php#L438

On the frontend, you’ll need to add an input field to the post form and then grabbing the form data so you can save it as activity meta. Check out /bp-default/activity/post-form.php for the actual form.

Saving the title might be a little tricky with AJAX though.

Thanks for the tip! I will see what I can work out