The roleplaying culture in the Realms of Despair adheres loosely towards the form of interactive telling of stories, where two or more characters meet and carry out narrative exchanges with each other in the form of poses or emotes usually in a static, chosen room. Roleplayers in the Realms also enjoy logging most of their roleplaying scenes which are edited to be posted and they read like short stories. There is more focus towards drama and reaction to imagined dynamic circumstances which are usually created as plot-lines by the players themselves.
Many roleplayers can be found in the Order of Sanctus Irae and scattered through the Nations. There are a few independent groups involved in faerie and vampire-related roleplaying. Some Orders like the Order of Arcanes and the Order of Baali also have their own active RP-sects that are usually ingrained into the Order's main theme. Roleplayers would currently make up 10% of Realms' general populace.
Roleplayers in the Realms have moved towards a multi-tasking age where they play a variety of characters, seldom sticking to one or two as in perhaps 6-7 years ago. Although characters do not level through RP and no experience points are gained by roleplaying, many roleplayers are not deterred by this hindrance and make low-leveled alternate characters (alts) just to roleplay with.
There is no rule to what the roleplayer can do in the Realms. Unless you belong to an Order with a set of rules and themes to follow, and which you must follow upon penalty; many a roleplayer belonging to the non-ordered sphere or Nations are allowed to be liberal in their creativity.
There is no overall Storyteller, Gamemaster or Dungeonmaster in the roleplaying community. (apart from the Orders stated in this article where there would be someone controlling the situation). Usually as long as a plot keeps within the logical, common sense acceptance level of most roleplayers, it would be eagerly engaged in.
For more explanation and ideas on how roleplay is like on Realms of Despair, you may want to take a look at the Roleplaying Logs as well as check out the Character Pages.