1) Add new button - "pay attention (or consider important etc)". For example, it is bad news, event. In this case it's not good to click "likes this". But it's important news and people want to make this news is famous. So, they can click new button, which can look like an exclamation mark(!)
2) I didnt see search robots (Google, Bing) in my site. If they are not visible, then it's good idea to make visible in admin.
3) I had problems with newsfeed in main. If I don't mistake, in this section you see newsfeed from all users. But I want to see newsfeed from only friends. Privacy plugin didn't help me. It's great to make newsfeed from only friends.
4) It isn't comfortable to delete posts using pop-up item. Why not to put the icon? And it's good to add the ability to send posts using 'Ctrl + Enter'.