I think when you use it everything will become crystal clear. The "clock" stands for timeline. The 13 next to it for the number of notifications and messages accumulated. If you press the timeline icon you get a list of other views (mentions, retweets, messages, etc).
The triangle/pyramid takes you all the way back to the top wherever you are. Tell me that isn't useful!
And andrex, thanks, that was really helpful. I am new to this ux so every little bit of guidance helps. The gradients you'll have to live with though
Thanks for the kind words, everyone! I'll make you proud!