The FAQ needs to be updated for specific stuff like that... but I'm pretty lazy, so it's probably not gonna happen.
Your best bet to find answers to questions like these in the future is to use the function. For example, after a quick search, I found this thread that answers your question about the User Reputation system:
It's old, but it will explain the basics anyway.
As for the titles under people's names, they are auto-generated based on your post count until you reach 1000 posts. The more posts you have, the more you progress to cooler and cooler poker names. Once you hit 1000 posts, in addition to other perks (like getting your very own, personalized TalkingPoker.com hat), you will have the ability to set your own user title.
Any more questions?
