I've been away from here a little while. Forgive if this is a somewhat abstract topic but it's something I've been thinking about a lot lately. I was asked a little while ago to work on a yield management app for the fitness industry (gym classes). It got me thinking that my ideal sort of business would be one that injected itself into a commercial exchange, which has had me thinking lately about what sorts of commerce have not been brought online for one reason or another. Maybe there really aren't any, but as lots of you run small businesses, I thought this would be a helpful/insightful thing to discuss. I suspect that if there are categories of products/services that haven't been brought online (or at least not successfully) it's because they are very high price and low volume (like real estate transactions) or of very narrow interest. Is there some commercial process you know that should be brought online but hasn't successfully been?