Whatever your feelings about Twitter, business plans are overrated, and profits perhaps even more so.
Why? Two reasons. First, because VCs are professional nit-pickers. Give them something to find fault with, and they'll do it with abandon. I generally tell people to come to pitch meetings with less information rather than more. Sure, you'll get pressed for more, but finesse it. Presenting a full and detailed plan is, nine times out of ten, a path to a "No" -- or at least more time-consuming than having said less.