Seth Godin has a great post about how all sorts of middlemen are disappearing or are in the process of disappearing from the market - travel agents, stock brokers, real estate agents.
In order to survive, middlemen can't just be an extra layer between the supplier and the buyer, they must either provide significant value or they will be removed by buyers. The reason is quite simple, the internet. Buyers can now research suppliers themselves. If I want to know the best price for an airplane ticket, I could probably call a travel agent, but it's far simpler to pop over to Expedia or Kayak.
I call this the Margin on Margin problem. Profit Margin is what businesses make each time they sell a good or service. If an airline company sells a plane ticket directly to me, maybe their margin is 5% of the ticket price. (Probably a bad example because I'm not sure airlines ever make money). If the travel agent sells me the ticket, they need to make a margin as well. That margin can either come out of the airlines margin or out of my pocket. The airlines used to split their margin with the agent but no longer. Therefore, travel agents have all but disappeared. The ones that survived, provide a different kind of value, perhaps setting up a complicated vacation with flights, hotel, sightseeing, etc.
In the outsourced billing industry which Billtrust is part of, the middleman role is often called a print broker. Print brokers work with billers to find a print/mail company to process their bills. I would guess that print brokers that simply act as middlemen are in big trouble. Those print brokers that provide billing expertise and perhaps a fuller solution will survive, the rest are going to be in trouble. Buyers are just too smart these days and the internet allows them to shop efficiently for the best price.
Who's your industry middleman? Are you one of them? If so, you might want to think about your value proposition.