Commentfic

Commentfic is fanfiction written in a comment on a LiveJournal (where entire communities exist for them) or website post. They are usually written in response to a prompt, in order to carry on the story in the post, or as a token of gratitude for the original poster.

Commentfics are often PWP, humorfic, smut, or fluff. Because of their spur-of-the-moment nature, they often suffer from a lack of spelling and grammar; however, depending on the author, they can be excellent little slices of fic, and very enjoyable.

Commentfic is generally too short to spork.