MapRoulette supports a variant of Markdown for marking up or styling text. Markdown can be used in most places where long-form text can be entered, such as task comments, challenge descriptions, challenge instructions, etc.
The variant supported by MapRoulette is inspired by Github-flavor Markdown (often abbreviated as GFM). Most – though not all – GFM is supported by MapRoulette. One notable exception: whereas GFM allows some raw HTML, MapRoulette does not.
Below is screenshot showing some commonly used bits of Markdown on the left, with a preview on the right of how that Markdown will appear to users: