I've never heard of Dustin Curtis, and I've said "you should follow me on Twitter" before. It's a pretty basic phrase, and I'd bet 99% of the people who use it haven't heard of him either.
I think you are right - 99% of people who use it haven't heard of him. However, they probably copied the idea after seeing it on someone else's blog. Apparently Curtis is the one we have to blame/thank for initially popularising this particular phrasing. I seem to recall he blogged about it being effective for him, and it quickly became the de facto postscript for bloggers wanting more Twitter followers.