While Google is not providing support for the App Engine because it is a preview, it has detailed documentation and a few developers dedicated to answering questions on the Google Group associated with the project, McDonald said. He acknowledged that the company may need to provide some type of support for people who would eventually pay for the service, but said no details have been worked out yet.

As for what type of Web applications are best suited to be developed and run on App Engine, Gibbs said any type of request-based, database-backed Web application would be a good fit.

"If you have an application that responds to requests from users and generates dynamic content to return that, it works well on App Engine," he said. "Some apps need an offline component. Now, we're still working to be able to support that. There are certain liabilities in the system right now that make it hard."

In addition, because response times for input or output of applications running on App Engine are limited to one megabyte for now, developers with applications that use videos or other large file uploads might find it hard to use, Gibbs said.

Gibbs also used the forum to tout App Engine's data store, which is made up of Google's Big Table persistence layer instead of clusters of SQL databases. Because of the departure from SQL, with which many developers are familiar, developers are faced with "a little bit of ramp up" getting familiar with the new APIs.

Even so, Gibbs noted, the Big Table offers better promise for scaling than SQL clustering. "Your application at any point in time is on a number of our servers. [Big Table] is fault tolerant, and any part can fail and the application can still run. It adjusts organically to hot spots and when application loads increase..., it allocates more resources to it. We use very little resources for an idle application. That is how we are able to run a lot of applications on average."