Strikethrough is used mostly to cross out something that is incorrect without actually removing it completely. Considering you cannot edit something already sent to the server and you can easily edit any line before it's sent, there isn't any reason I can think of for adding that to mIRC. Do you have a valid reason for it?
Why have it on forums, then? Or have it at all on a computer when you can most likely just completely erase something instead of striking it through? I don't have a valid reason for the color codes, bold, reverse, underline, or italics beyond to make certain things look more appealing. I'm not trying to sound rude. Sorry if it sounds that way.
Edit: I tested what you posted, jaytea. Looks cool.
