Some businesses fall in the middle ground of Few vs. Many, or we can say evolve to a state which is encompassing more than one of the two rigid blocks (few and many). They start with one and develop into other. More common is the scenario where you start with a niche area targeting a few big customers and slowly the market expands and evolves into a mass market.
For example Customer Relationship Management services. It started with big corporates looking for highly customized solutions to manage their customers. The big players in this business are companies like Oracle and SAP. Slowly small and mid-size businesses started looking for CRM solutions and providers like Salesforce and Microsoft Dynamics emerged in the market.
Another example that comes to mind is stock trade. Years back stock trade was done by a few financial houses and businesses working at the stock exchange. Now there are dozens on online brokers like Etrade, Ameritrade, Scottrade etc. and any individual can participate in the market.
Internet has been a big enabler of getting the service to the many due to a couple of reasons. First, scalability. Internet has drastically reduced the scaling cost of various services. Second, customer service and support. You can use community site to support your product or service. This is a fantastic way to provide support because then you can use the community power to improve the product as well.
The interesting thing to understand here is when the business shifts from few to many, most of the times the major players changes as well. This states that it is completely a different ballgame when it comes to serving the many as compared to few and the companies that are focused towards serving the few cannot shift gears that easily to serve the many. Few big difference: a different pricing model, a completely different way to connect to customers (physical to virtual) and adapting to different technologies.