Google is offering to host your web apps for free:

You can create an account and publish an application that people can use right away at no charge, and with no obligation. An application on a free account can use up to 500MB of storage and up to 5 million page views a month.

What’s an application? It’s a runtime for Python apps (only Python code will run) and includes the Django web framework. There is a structured datastore which on the briefest of looks has echoes of Amazon’s SimpleDB and Microsoft’s SQL Server Data Services. Welcome to GQL – the Google Query Language. You can send email through Google’s servers (hmm, hope some work is being done to foil the spammers). You can use Google Accounts as an identity service – this is a big one, since it helps Google to meld your online identity with its services.

So what’s the business model? Google says:

During this preview period, only free accounts are available. In the near future, you will be able to purchase additional computing resources at competitive market prices. Free accounts will continue to be available after the preview period.

There are a few clues about what will constitute an “additional computing resource”. Clearly storage is one limit, and there is also a limit of 3 applications for free accounts. There is also a reference to bandwidth limits, the number of results you can return from a query (1000), and the length of time taken to serve a web request.

Apps communicate through HTTP or HTTPS requests. No talk of SOAP or even XML that I can see, though presumably you can use Python libraries.

Although we talk a lot about the largest applications that need to scale, this is a minority of real-world applications. Many of today’s web applications could run happily for free on Google’s new service, once ported. The economics interest me. Google is offering to subsidise our web infrastructure even further than it does already with GMail, Blogger and iGoogle gadgets. Therefore, if we choose to host our own services we have to pay for the flexibility and control that gives us, as well having to deal with scalability and security issues that Google will otherwise look after for us. In the light of generous app hosting offers like this, how much are we willing to pay for that freedom?