Some interesting facts about Google App Engine

Google App Engine is awesome. So beyond this simple fact here are some other interesting ones:

Account Registration
For the first time you click on "Create Application" (https://appengine.google.com/)  You need to sign up with a phone number. Facts:

• If you try this without a supported carrier (mentioned here) You will start to get the error message "You have sent too many SMS verification messages" In this case goto http://appengine.google.com/waitlist/sms_issues and mention why you are getting this error (your phone number). Your case will be evaluated and if found eligible your appspot account will be activated.
• You phone number is linked to your google account. You cannot use the same phone number to register for appspot using another account. 

Application Registration

When you create a new application not all options will be changeable. At the time of this writing you can see options which are available for change and which are readonly (Authentication Options used to be readonly as well apparently but as you can see I can change them right now):

And since you cannot reuse the application ID it is important to set it right the first time.

Download Application Files
There is no way to download files from AppEngine (you can only upload....this actually makes me feel secure). So you should use your own version control system (I suggest http://www.bitbucket.org)

AppEngine is designed for fast response times
If an app routinely takes a long time to respond to requests, AppEngine will punish it to make room for faster requests.

Enjoy!