Okay.
RPG was made by Mahz in 2007 (then known as Mahzkreig, correct me if I am wrong), as a roleplaying site. It was intended for this use, and has run for a mainly successful 7 or 6 years. Guild was taken down late 2013, came back early 2014
There are 3 sections.
Free - This commonly consists of speedposting* (see below), and short one-liners* (see below). These have many threads, but I do not recommend it for starting out, as with the one-liners, it is bad for your future self, and will probably make your future posts short and useless.
Speedposting - posting in a very short amount of time, almost a few minutes from each post. Ends up making a lot of pages to read over. Recommended to make a rule against this, with 2 people posting before you can post. It is the common rule, and a well-known one.
One-liners - One line in a post. Usually, there is little to no detail in this.
Free is home to some long-running RPs, one being for 3 and a half years.
Casual - The commonly recommended starting place, and the most popular of the three. This normally requires a good amount of detail and character development* through the RP, and a paragraph* or two. Usually no one-liners in this.
Character Development - The name of developing characters' personality through the RP. Not required through every post normally, and happens on occassion. Usually makes it so the character is different from when they started out.
Paragraph - 4 or 5 sentences to make a good paragraph. No run-on sentences should be in these. The norm for Casual.
Sub branches - HighCasual -- a more advanced version of the casual you normally see. Usually 4 or 3 paragraphs are in these posts, at least I have heard, and sometimes has collabs*.
LowCasual -- A less advanced version. More laidback than regular casual, but less than free. Does not need paragraphs sometimes, depending on the GM.
Collaboration posts - The combination of two writers to make one (usually) long post, sometimes consisting of relationship development or character development in these posts. Sometimes, these posts might take an hour or two to make, or maybe more. Is normally for Advanced or HighCasual.
Advanced -- The least popular of these. Normally, there is lots of waiting to get these started. Probably a week or around that, for everything to be ready. And even then, you will have to wait for posts. There is almost no speedposting, but lots of collaboration posts. More like a novel, with character development.
Thread - A thread. You created one, and I have posted in it.
Character Sheet - A sheet for your character to join in an RP. You fill it out, usually with detail unless you don't have to, filling out the required forms and making a personality and history, along with name, age, race, and other such things.
GM - The GameMaster. The original maker of the RP. Sets the rules, and accepts characters. Hires a Co-GM.
Co-GM - The Co-GameMaster. Helps with rules and the GM's job.
WIP - Work In Progress. Usually for a Character Sheet that is unfinished, and is going to be edited.
Edit - To edit a character, usually adding, taking away, or fixing parts.
Quote - To press the quote button, usually for something another player has said, or to specify who you are in fact talking to. Sometimes to agree with something.
From Jig: A good thing on meta-gaming.
Meta-gaming. When your character has a secret, even one that could be easily found out by the proper methods, that other players are aware of, and suddenly one character has this bolt of inspiration that enables them to instantly work out what the secret is despite having absolutely no information about it and not having embarked on any means of research to find it out.
BOOM.