I'm not quite sure why this was happening or why but I just thought I'd let people know.
For about 3 minutes I was unable to type into any of the text fields to reply to a thread or PM. I could paste pretyped inputs, but I couldn't add anything from the keyboard. It was exclusive to E so I don't know what it could have been... I tried clearing my cookies and that didn't fix it. I'm not sure what did honestly...
There are a lot of bugs involving the WYSIWYG editor and I should probably force-turn it off for everyone.
Usually, this sort of thing is the result of one of the Control/Alt/Meta (apple) keys thinking it has been pressed but not released (When you press a key, it sends a signal. When you let go, it sends another - so it's possible for them to get 'stuck down' on occasion).
When it happens, try tapping each of your control/alt/windows/apple keys - both sides are separate keys - once.