I don't see (or maybe I'm just not noticing) any multiplayers on, that is, people playing 2 or more characters at the same time. The policy seems to allow it (from the same account, of course). Is it just not a popular thing on Tempus, or discouraged, or anything like that?

You may have one account with multiple characters on it. The game only lets you log one character at a time from that account, thus enforcing that multiplaying is not allowed. If you type 'policy' in game you'll see this section.

Ahh, okay. I did read it, but I didn't catch that part I guess.