Just a suggestion if you can implement. Why not display a message along with the counter that says one of the following messages depending on character/word count? -
< 15 words : Post too short!
15-100 words: Looks like you're typing something nice
100-500 words: Salute, typing master!
> 500 words: Hope it's not a copy+paste job
..would make posting business funnier (maybe!).