Much of this is explained in the FAQ, actually.

Also, the little dots by everyone's name... If you hover your mouse pointer over them for a second, they instantly become self-explanatory.

As for the user titles, the forums has a set of user titles based on the number of posts the user has made. However, a user may also select their own title by editing their profile.

And again, this is explained when you open your User CP and select the Edit Profile options.