That was very much part time, I could knock out 100 tweets in 10 minutes. I would block them in 4-5 periods a day. It's incredibly quick, easy work.
I'm assuming this is hyperbole, since that actually turns out to be like a question answered every 6 seconds -- but what kind of questions were you answering in volume like that? I'm curious because it seems to have had such a large impact on your bottom line.
$5,000 a month is great, but where is the growth in it? Plus it leaves you little time for much else.
There is little meat on the bone left over if you are paying someone to tweet for you.