Wow! You're getting a lot of great ideas in this thread, Hugh.

In my little post yesterday, I was referring mainly to the business if contacting business offline and creating websites for their needs. I haven't done it myself, but some enterprising web creators will even build a generic niche site for, say, a regional profession, rank it high in search, then offer it for sale or a monthly rental fee to local professionals. And, of course, there are website creators who simply build a niche site with Adsense or something to show income, then turn it around for a quick profit. There are sites that allow you to post such sites for sale.