ask that question myself roundabout twice a day.
We have a company website (www.intex-publishing.de), a shop (www.intex-shop.de) and x product websites like www.hausverwaltung-pc.de and www.fahrtenbuch-pc.de - all of them have the same look&feel and are interlinked between each other.
This all grew in years of development and can´t be maintained with a CMS, so we do it with RapidWeaver.
Rapidweaver is kind of a brother/sister of FileMaker in the respect that I love and hate it at the same time, but there is no real alternative.
Would be nice to have all information on one big website. Would make changes easier, navigation would be straightforward, but we have the impression that Google wouldn´t like it that much. I have the impression that for SEO purposes x websites are better.
lol yes I also ask it frequently but thought I would say it aloud for once.
Im thinking the same as you regarding SEO, its a bit messy for us but I think its probably the best solution at the moment and looking around I see a lot of companies to it, even Microsoft.
I used to do that way in 2004. It did help at that moment. I had one "main" site and 4 copies with different domain names. All 4 of them pointed to the main site via small descriptions and inline frames. So the content was not really duplicated. I was always on the first page and my competitor at the time was on page 2 :-)
But Google wasn't Google then, and I think I used AltaVista at that moment for searches.
They have changed the ranking system a lot and it's a lot smarter. Today it's just a total waste time if you ask me.
Just make one nice site, watch the code/text ratio and put relevant headers on top of paragraphs.