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 …

BuddyBoss

Let your BuddyPress members edit their activity posts and replies on the front-end of the site. You can even set a time limit for how long activity posts should remain editable.
Just activate the plugin, and every activity post and reply will become editable, styled automatically by BuddyPress to fit with your theme.

BuddyPress Edit Activity

BuddyPress Edit Activity allows your members to edit their activity posts on the front-end of your BuddyPress-powered site.

Buddypress Activity Anywhere vs BuddyPress Edit Activity