A new term describing a FanFic that has been written to alter or 'fix' the original works.
Usually it concerns things in a certain book/film/series etc that didn't work or the author didnt want to happen.
Alot of Torchwood enthusiasts have recently been doing this with the 3rd series - Children of Earth. To avoid/change certain events that happened, most likely in episodes 4 and 5.
Alot of debate has gone on concerning the writings for this series and the uproar suggests more of a fix-fic rather than fan-fic.
A "fix it fic" is a fanfiction where the problems are solved. Characters who were originally dead in the actual books, shows, or movies, are now alive and well... catastrophes are prevented by the author of the fanfiction and (almost) everyone gets the happy ending they deserved, but never got in the orignal work.
In a Harry Potter "fix it fic" that I read, Cedric Diggory, Sirius Black, Fred Weasley, Remus Lupin, and Nymphadora Tonks all lived to be happy and safe like they should have in the books!