The UK's Met Office - who provided Weather Forecasts use it for their new Weather Observations Website (WOW): http://wow.metoffice.gov.uk http://wow.metoffice.g

The UK's Met Office - who provided Weather Forecasts use it for their new Weather Observations Website (WOW): http://wow.metoffice.gov.uk http://wow.metoffice.gov.uk It's a site that allows the public to submit weather observations from anywhere in the world. Since launching 31 days ago, we've got 1.7 million weather reports and probably spend about 0-30 seconds a day (on average) on maintenance. App Engine has some big pains (SSL has already been mentioned) but if you don't require it (we don't), I think it's a fantastic tool. The multiple versions, quick deployment (new build inc all testing&configuration can be completed by us in <5 min), automatic scaling and the fairly good dashboard are fantastic. Plus, our infrastructure costs in development (before heavy load testing) was $10 for 3 months of work - absolute bargain! Even after heavy load testing, it was a fraction of what a real server would have cost. I'd say the biggest difficulty (or barrier to entry) is the datastore design. It's very easy to think you're in SQL land, and you're not. And because of that, it's very easy to burn yourself quickly. But, the design gives great scalability. We wouldn't be able to manage the size of the data we're expecting in 2 years+ in a typical environment. So, I think it's great :) (Disclaimer: I was part of the team at PA Consulting that built WOW)