"thats good to hear""oh me too""are you sure?""you're boring">:)
Yes they can see a reply if they click on their @replies. That's how you get to know peeps on Twitter!
You'll see your mentions if you click on your username or you could click on your @username and you'll see people who sent you messages
You answer with xoxo back. xoxo are kisses i think .
"I am well, and you?"