Derech HaMelech:
1)  I’m not sure what you mean by “make it look like it is in its own thing,” but I think you mean “blockquote.”  You do this by putting <blockquote> before the quote and </blockquote> after the quote.  Also, you can always set off the quote by putting it in italics.  You do this by putting <em> before the quote and </em> after the quote.
2)  If the person starts with your name (as I did), then you know it is in reply to something you wrote.  If there is no name, you just have to figure it out from the context.