I wasn't sure if that was client-side or server-side, and, if client-side, if the filtering is done at submit-time or display-time. I have seen someone tweet so

I wasn't sure if that was client-side or server-side, and, if client-side, if the filtering is done at submit-time or display-time. I have seen someone tweet something with many sequential newlines, so I figured that it was probably client-dependent (I use Tweetbot).