I know it's a tad off topic, but it's really annoying me. How can I change it? I used to think it was either for premium members or for members with x posts (more than I have). However, I swear I saw someone wearing a custom title with below 150 posts (less than me). Any clues?

When do the titles under our names change and when can I make my own?
Posts Status
0 New Member
2 Newbie
30 Junior Guru Wannabe
100 WHT Addict
175 Junior Guru
250 Web Hosting Guru
350 Aspiring Evangelist
450 Web Hosting Evangelist
550 Web Hosting Master

A custom title is available after 550 posts AND 90 days of membership.

http://www.webhostingtalk.com/helpdesk/?_a=knowledgebase&_j=questiondetails&_i=3

Ah OK, must have been my stupid mistake when I "saw" that guy with 150 posts and custom title. Cheers for clearing that up ;)

That would be someone that posted mainly in the advertising forums. Posts stopped counting a while back in the ad forums. If you check all posts by that user, I think you will find he/she has over 550 posts ;)