When I am creating posts to a social set, I am reminded of Twitter's 280-character limit. Evidently, LinkedIn has a character limit also, of 400, but the interface does not tell me that -- the post simply fails afterward.

It is up to me to make sure that my LI posts stay under 400 characters, and that is challenging. It would be far better if the service kept count and did the whole red-text thing, as it does with Twitter.