I just don't get it...

I went to this great talk today on local area marketing...you know, business stuff. Any way apparently you've got to have online presence these days, website (check), Blog (check), Facebook (check) and you absolutely must Twitter!
Being the NON-early-adopter that I am, I've resisted social networking sites for years. Recently I caved and joined Facebook. Strictly for business reasons...but now I really enjoy using it for personal stuff like sharing photos of Emma with faraway family and friends etc...
"But that's where I draw the line..." I told my sister"...you won't catch me tweeting!"
So when Debra Templar, Retail Guru extraordinaire says you must Tweet, well then I may have to re-think my position.

So I've been trying to work it out, doing research...but I just don't get it!
Help me out here guys! Am I missing something? So far this is the most informative thing I've come up with, and it sort of re-enforces my position. And it's funny...