Ummm, earn one? As far as I know the highest title you can receave (based on post count) is sonic. I got that title a while back, I asked for a custom title then, and Skankin Monkey + Arakon had a little bit o fun messing with it (As you can see).
Oh, and just for refrence Ringwraith, here is a partialy completed info table on what titles you get for your
number of posts:
Fresh Meat: 0-?
Sega Nut: ?-115
Robotnik: 116-160
Tails: 161- around 370
Sonic: Around 370-380 (Final title)