What's the "master" database in SQL Azure for? I just created a subscription and once I created a "new SQL Server" I immediately got "master" database with 1GB size. That database can't be deleted - "delete" button is not active in the management portal.

When I tried to deploy a .dbproj project there Visual Studio said it "couldn't deploy to a system database".

Can I use that database for storing my data? Do I create a new database instead?