Word in the corporate sector is that Microsoft is planning to use Visio as its test "subscription-purchased, server-based" application. Basically you'd pay a monthly or yearly subscription on order to use the product which will not run on your machine but remotely on a large server. Thie would allow the application to be used from other Microsoft-pushed products such as WebTV.

I know this because I worked for a company through which microsoft was looking to buy hardware to set up the necessary infrastructure.