As you might know, Amazon offers some web services for data storage, virtual servers and database.
From the research we did for a customer who wants to host Etano community builder on the Amazon platform, the virtual server solution works with no problems with Etano.
The great thing about this is that the virtual server is "elastic" - you can add resources (disk space, cpu power, memory, etc) to it on the fly, no need to purchase another server and move your site to the new server.
However, the prices for all services can be a little prohibitive if you start consuming too many resources.
Until now Amazon was the only company to offer this kind of services (as far as I know). But this has changed. Google revealed yesterday their new platform for application hosting and development.
And it's free. Not entirely but for web applications with less than 5 million hits / month this really is free. And the best thing is that it too scales so you could grow from 1 to 100000000 members and your site would still work.
For now they're in beta and support only the Python programming language but they promised support for more languages (including php, of course).
This is great news for Etano owners. This could mean that you won't have to pay for expensive hosting and you won't have to fear that your server will go down in case of a sudden surge in members or interest in your site.
