I'm glad you ask.
Actually for English-speaking users it won't change anything. Since all the ASCII codes for English characters are implemented in UTF-8 directly, everything will remain just the same, except you'll notice that weird alphabets like Chinese, Japanese and Arabic suddenly start working instead of showing up like garbage. So even weird messages in languages you don't understand won't be so )()"!)"=#( annoying anymore.
This is the only change, and it's also a positive one IMO. =D
