Demographics R us

I'm not a Luddite but by today's standards I would be considered a computer illiterate. I wonder if there are others like me, of my (advanced) age who are still fairly articulate  and who are trying to communicate to an unknown audience of like-minded people. What are the demographics?  I read of this young girl who started a Twitter when she was eleven years old and then an e-magazine, with an estimated audience of some 500,000 people - young people like herself.  How many people of my age are there out there, that is, people who read and write blogs?  My computer guru suggests there are more than I might think, and that's comforting.  But I think my targeted audience is younger than that, than I.  I want to reach the Boomers, the generation I was partly responsible for. They've got two worries: one, how to look after their parents (like me) because the old folks are  living longer and running out of money and marbles; and two:, how to prepare themselves for a long, long future. Hey! I'm here. and I want to  help. .