This page is the activity stream for diaspora*. This page lists the current posts and comments. It also gives the user the opportunity to comment on other posts. From this page you can also invite your friends, get help, donate and bookmark…
On this page, you can see the individuals who are using/following a specific hashtag, in this case it is #socialmedia. From this page, you can post information relevant to this hashtag and those who follow it, will be able to see your post.