It seems best suited for small, focused applications that are developed quickly and expected to live hard and die young (lots of traffic for a short amount of time).
I can also imagine applications that designed for the user to be able to install it on their own AppEngine account. Maybe something like Wordpress for GAE, or imagine a distributed/federated version of Twitter. People might find a new app very useful, but have concerns about investing time and effort in an application from some startup that could vanish on short notice. If they had it instaled on their own app engine account, they'd at least have a chance to move their data over to another application before entropy took its toll.
I can also imagine applications that designed for the user to be able to install it on their own AppEngine account. Maybe something like Wordpress for GAE, or imagine a distributed/federated version of Twitter. People might find a new app very useful, but have concerns about investing time and effort in an application from some startup that could vanish on short notice. If they had it instaled on their own app engine account, they'd at least have a chance to move their data over to another application before entropy took its toll.