Xeround: Elastic MySQL service in the cloud

After some hunting and pecking this seemed to answer some of my questions: http://www.xeround.com/developers/faq.html

- It runs on EC2.

- For performance, they store data in memory (backed up on disk). So it should be faster than regular mysql (but use more memory).

- It's a drop-in replacement for MySQL (it's a storage engine). Your code doesn't have to change at all. (ie. you can use PHPMyAdmin etc...)

- It scales up and down quickly, supposedly (although I couldn't find many details on how).