But it seems that a lot of businesses hardly do this at all. They just use their Pages to announce sales, discounts, events and other promotional stuff. Of course they should be doing all this, but they should also be trying to generate engagement as much as possible.
I suspect that a lot of people in business don't get conversations going because they can't think of what else to put up there. My advice to them would be that you don't have to generate all that content yourself. If you're in business you'll be keeping up to date with news related to your industry. So you can link to those articles and ask for input from your fans. Then once you've received some comments you'll have something else to write about.
Also, much like with blogs, if people arrive at your Page and see that it's active with lots of reader input, they'll be more likely to write their own comments.
Then there's the effect that activity has on Facebook's inner search algorithms. Sure, the social network is nowhere near as sophisticated as Google in this regard. But more activity and engagement are sure to make your FB Page easier to find within the site.