ASP - Application Service Provider
ASP, a third-party entity that manages and distributes software-based services to customers across a network to reduce the cost of software distribution and maintenance. It's a good alternative not only for smaller companies but also for larger companies as a form of outsourcing Software.
ASP model is sometimes called on-demand software. Application Service Providers like Salesforce.com, Clickability and WebEx provides services of ASP.
ASP – Active Server Pages
Active Server Pages is Microsoft's server side scripting technology that enables you to make dynamic and interactive web pages (Web sites, Web applications and Web services). Web pages build with it have ".asp" file extension.