Standard browser client, host OS, and IP RDNS lookup -- all standard parts of the internet TCP/IP and HTTP protocols.
Not only that, but they can tell you what VERSION of the operating system and browser you're using.
This has been common on web pages since the mid-90's. It always gets my attention, I admit...
Can you add a line to pull up what I think of Obama?
Ah, but then I would undoubtedly be banned.