If you want to write something alone, why not notepad, or google docs, or microsoft word? The idea is that it wouldn't be a level playing field if you could compete on the rankings page with something you had more direct control over.

As for duration... I can't really see it being used over a long span of time. Even the 2 minute duration is too long if it's more than 2 or 3 authors in there. 1 minute really gets the creative juices flowing and instantly makes it immersive as you always can't wait for the next line--and you don't have to!