It's somewhere around 1/3 for me too.
Then there's another 2% of the time when I press cancel instead of post, by accident, deleting my post.
I decided not to post a 92 lines long post once. That was rather amusing (instead I bugged some people by posting it at their walls. Hah!)
http://www.vgchartz.com/games/userreviewdisp.php?id=261
That is VGChartz LONGEST review. And it's NOT Cute Kitten DS