Yesterday Google unveiled App Engine and App Gallery, which some bloggers have likened to AppExchange. But it's really quite different.

First, what is App Engine? Like Force.com, it is a web app development platform-as-a-service. App Gallery is the directory for sharing apps built on the App Engine.

There are two important distinctions. First, the platform and apps at least right now are focused around the Consumer Web, for example games, news, finance, sports, etc. Second, as shown in this Youtube clip, App Engine development is more focused on code-driven development.

Force.com gives application developers a choice of code or clicks (or both) to build, customize, and integrate. App Engine fills an important gap for building, hosting and sharing consumer web apps - and we expect to see that across App Engine and AppExchange, more and more people around the world will be able to make their personal and professional lives easier with platforms-as-a-service and generally the On-Demand model.