Skype Prime is included in the new Skype 3.1 beta on Windows. Skype Prime allows you to charge a one-off or per-minute fee for people to call you. Perfect for premium rate voice services. But what else does it enable? I've talked about Skype as a platform before. What automated voice services could be built--perhaps, simply, a voicemail system as a front-end to a dictation service? It could work like this: You call a number, which happens to be running on Skype. You pay a per-minute charge, and dictate a message. The call is recorded and when you hang up, the mp3 is pushed to Mechanical Turk for transcription. The text is emailed back to you. Of course there's no reason this couldn't be done with Asterisk or some other transcription service, but the advantages here are: Skype has micropayments built in; you can run it from a desktop machine; the technology makes it easier to prototype so you can concentrate on the experience.
What else? The one-off payment means Skype Prime could be used for software distribution. You pay your money, you get a file in return. Granted, it doesn't scale well and software distribution can happen in many ways... but for an individual selling home-made ebooks or movies, a simple plug-in to allow this could be easier than setting up online.
Given all this, if I was Skype I'd be working on a server-side Skype component. I'd want to allow, for example, Ruby on Rails apps to run dynamic voice menus, call in and out, and offer premium services.