Eyal Fitoussi

This is a simple that adds an activity button to the admin toolbar in the fron-end. Once a user (logged in) clicks on the button the activity form will pop up. The form will have a text area for the user to enter anything he want to post in his activity. 
When the user submit the form the plugin will post the info to his activity stream.
Checkout the <a href="http://codecanyon.net/item/buddypress-quick-activity/7112239" rel="nofollow ugc">premium version</a> for extra features

Buddypress Activity Anywhere

Let the members of your site post an update to their activity stream from anywhere in your site or any other subsite in a multisite installation inste …

Henry Wright

Muting results in the muted member’s activity items being removed from the activity stream. Muted members can be unmuted at any time.

BuddyPress Mute

Let members mute their friends and shed unwanted items from their BuddyPress activity stream.

Buddypress Activity Anywhere vs BuddyPress Mute