Roulettes
I've grouped two of "roulette-style" websites on this page (and hope to add more...) so it is a bit hard to define such a broad category of roleplaying site in a few short words, but we're going to try. A "roulette-style" roleplaying website is designed to match you with other anonymous partners more or less at random. Some websites have a set of (often optional) parameters (such as the style of roleplaying, whether it's script-based or paragraph-based) that you can use to refine your search.
Due to the often unpredictble nature of roulette-style roleplaying, pinning down exact cultural nuances is more than slightly difficult. That said, they generally favor script-style roleplaying, but it's not at all impossible to use them for paragraph-style roleplays. Some roulette sites, such as Omegle, are 18+ and not actually intended for roleplayers, while sites like Rolechat were designed explicitly for roleplayers.
Omegle
Omegle.com is an 18+ anonymous chat roulette-style website. Given the instant-messaging style of the platform, it heavily favors script- or instant message-style fandom roleplay, but paragraph-style roleplaying isn't unheard of. On the front page of the website, you can enter your "interests" (henceforth described as "tags") in the box, and then Omegle will attempt to match you with people with the same tags. If it fails to find someone with the same tags as you within a few seconds, it connects you to a random stranger.
Often, the tags are the names of pairings from your fandom, such as "Pharmercy" or "Wrightworth," and the chat is assumed to be between the two characters in question. It seems the most popular way to roleplay on Omegle is by pretending the characters themselves are sending the messages, often implied to be texts on a phone (or the fandom's preferred form of text-based communication) received in real-time.
To indicate which character is speaking, the messages are often ended with the initials of the character, such as:
Have you seen my glasses? AZ
It's not uncommon to see people put some kind of indicator at the end that the initials aren't part of the message, though. "Are you sure? - AZ" would also be acceptable.
In the case of AUs, or other kinds of information about the roleplay, supplementary information is usually added in OOC parantheses before or after the starter.
I know what you did. - PW ((Takes place slightly before the start of AA4))
Or perhaps:
((College AU; Y/C and Ryouko are roommates)) Have you seen my notebook anywhere?? RO
Generally, AU information is put up front, while other pertinent information—such as where in the timeline of a piece of media the roleplay takes place, for example—is appended to the end. However, this is not a steadfast rule.
Paragraph-style roleplaying is much the same. You describe any important information OOC up front in parantheses, and then post the "starter" (one to several paragraphs to start the RP.) While paragraph-style roleplaying definitely isn't the most popular form of roleplaying on Omegle, you do see it fairly often, especially in older/more established fandoms.
While Omegle is explicitly 18+, it is extremely possible that it is still frequented by minors, so please be vigilant. The anonymous nature of the website makes it difficult to determine who is and is not a minor, and people are liable to lie about their age. Some people will occasionally use OOC to indicate that they are looking explicitly for other 18+ users, but this is obviously not a foolproof plan.
Rolechat
Rolechat is an anonymous chat roulette-style website much like Omegle, but it's specifically designed for roleplayers. It can be used by anyone 13+, but it does have a dedicated 18+ section in which NSFW content (both sexual and gore) are allowed. Due to the instant messaging style of the platform, it slightly favors script-style roleplaying, though paragraph-style roleplaying is possible, prevalent, and encouraged.
When you click the "settings" button, you can pick which server you wish to be on (all ages or strictly 18+,) as well as add "tags" to find other roleplayers. I assume it works similarly to Omegle, in that you are to enter ship names, but I imagine that entering a fandom alone is also an option, as the site is explicitly geared toward roleplayers in the first place. In addition, you can also select how long you are willing to wait to be matched with another user.
On Rolechat, it seems that roleplayers without tags tend to put the important information in their names: you see people named things like their fandom (if there is one,) their preference for reply styles (paragraph or script,) their character's gender or sexuality, whether or not they have a starter, or, in the case of original characters, usually a short physical description of the character and possibly some other relevant modifiers.
(If you use Rolechat and would be willing to talk to me about it, please consider contacting me!)
This Page Could Be Better!
If you know any other roulette sites, or have other information about roleplaying on these sites, please consider contacting me to share what you know! At some point one of my roommates got us IP banned from Omegle (???) so I can only go off of what I remember and what other people tell me. Your input is greatly appreciated!