Google Maps seems to do a pretty good job of parsing addresses. Given a database of say, US city names, state names and zip codes, could an API not be built that would recognize something like that and wrap it in a microformat either by a stupid simple API call or just as an auto-expanding template type feature?

I agree with you that the average user (which includes business, etc.) will not do it significantly unless it's effortless so I wonder if app platforms or frameworks can make it more effortless in this way. That combined with some level of justified business value in some sectors could be our best stab at a practically, usefully, partially semantic web.

Being pragmatic, I'm not one to say that unless the whole web is semantic then we give up. I'm also not one to believe the whole web will be semantic or that all of it really needs to be.