The category with the most promise is the critical-mass ASP. Critical-mass ASPs have an application service on which a large industry or a big portion of the entire market relies. Their focus can be horizontal or vertical in nature, and their business model must be able to scale to support the number of users needed to reach critical mass. Their service is typically unique and addictive in nature. This category provides the service provider the best opportunity to sustain a differentiation strategy. It's also very difficult to recognize in the early stages, so it can be easy to miss the boat entirely.
Service providers looking at the ASP market have many things to consider. Deciding whether to enter the space at all is a huge question mark. But if that decision is made, looking at the category in which prospective ASP services fall will help determine whether or not the venture will be successful.