BuddyPress allows you to share updates, little stories. Get control over BuddyPress Activity using these plugins, best part all of them are FREE!. You can also use 3rd party plugins like BuddyPress Activity Plus which adds Facebook-style content sharing buttons to the BuddyPress activity feed so users can quickly share articles, videos, and images with others.
BuddyPress Check-ins allows BuddyPress users to check in their location as part of an activity update.
BuddyPress Post from anywhere also help to publish updates for anywhere using shortcode inside the template files or widgets. BuddyPress Activity Shortcode plugin allows you to embed BuddyPress activities in posts/pages using shortcodes.
rtMedia for WordPress, BuddyPress and bbPress is the only complete media solution for WordPress, BuddyPress and bbPress. MediaPress is also a good alternative, You can also give a try to it in the initial phase, not making a suggestion to switch at a production site.
Few more addition- BuddyPress Activity Social Share allow anyone easily share BuddyPress activities on major social media (Facebook, Twitter, Google+, Linkedin ).
BuddyPress Activity Filter allows to set default and customised activities to be listed on front-end. It will also allow to set your default option for activities. You can change default from everything to Post Updates.
It was all about activities, if you also have some plugin which modified BuddyPress Activity or enhance it feel free to drop links inside comment area.