How? By using your Activity Points in the Marketplace!
Activity Points (AP), for those new to the term, are points that you accumulate every time you do something here in the site from posting comments, uploading images, videos, and so on.
To see how many Activity Points you’ve earned, you must first log into your account and in the Dashboard page, look for the link called Account Info or Activity. Account Info will give you the total sum of Activity Points that you have while Activity will list a detailed account of everything that you’ve done at the site.
If you’re interested in having a custom forum rank, you will need 1000AP. Also up for grabs is the choice to change your username for 500AP but only if you’ve already used up your one-time change ability.
In future, I will be listing some more including a chance to get bigger signatures in the forum and even coloring services from yours truly.