All the "special" ranks are individually handed out by staff members when they feel someone has deserved it. Rep and post count are not taken into consideration. Friendliness, personality, & just overall behavior past and present are pretty much what is taken into account. The ranks are color coded to each other (Bit Legend, Bit Technician, Bit Reporter, and Bit Loader+ are all equal in rank for example). Obviously, the higher the rank, the harder it is to receive.
Here's the basic lowdown on them, grouping the equivalent ranks together via the same colors:
Bitlet: A member of 128bit! No special status, just a normal member.
Bit Hero: Bitlets who stick out in the community in a good way in the eyes of the staff. Trustworthy & consistently good behavior.
Bit Loader: Bitlets who have uploaded a fair number of games (GC, Xbox, PS2) to the site. The number of games required is 15.
Bit Legend: For bitlets who have already achieved a Bit Hero equivalent rank. They're helpful around the forum, contribute a lot of positive personality & good discussions, have very consistent positive behavior, etc. You get the gist of it. Basically an "elite" status.
Bit Reporter: A Bit Legend, but with the rights to post new threads in the News section.
Bit Technician: A Bit Legend that has been particularly helpful with technical issues in the Help boards (People who clearly know their stuff with Dolphin and/or console mods and can accurately & quickly help others with related issues)
Bit Loader+: A Bit Loader who has uploaded a lot of games. The number of games required is 50.
Bit Mod: Global forum moderator. They enforce the rules and manage forum posts. When a mod or admin tells you to do something, you better do it.
Admin: Self-explanatory. They do everything around here.
Post based ranks are seen for all bitlets who have not achieved a higher rank. Each rank is related directly to post count in boards where posts are counted. Do not spam to get a higher post rank. The ranks listed above mean more than any listed below. If you spam to get one of the ranks below it can jeopardize your chances of reaching a rank above.
0-bit: You just joined!
8-bit: 10 posts
16-bit: 50 posts, able to give reputation!
32-bit: 100 posts
64-bit: 200 posts
128-bit: 500 posts