I just got an error message when I tried to post something saying the content I was trying to post was too long. This is the first time I've seen this message. It was very frustrating to get this message after spending soo much time typing the post out on my tiny phone keyboard. If you plan on having limits on the length of the message you should consider adding a feature that allows the user to see how many characters are left while they are typing. Also, having a message that says that the post is too long is pretty useless if you don't define what you consider to be "too long." Some indication of character limits even in the error message would help.