Henry Wright

Here makes use of the WordPress Transients API to keep a record of who’s currently online. A green dot will appear next to each active user.

Here

See who's online now on your WordPress site.

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.

Here vs BuddyPress Edit Activity