BuddyPress.org

All of the content that is output with bp_activity_content() is stored in the database. This is mostly for performance reasons. If this data had to be recreated on each page load, you’d be looking at hundreds and hundreds of queries.

You can modify it with a filter though, but you’re limited to string replacement and css modifications:

function my_function( $content ) {

return $content; // do something with the content first

}

add_filter( 'bp_get_activity_content', 'my_function' );

You can put this in your own plugin, or in bp-custom.php.