Lets you create and download SQL dumps of your wordpress database for backup.
The plugin don't have a restoring facility yet. You will have to restore it manually using the phpMyAdmin interface available from your control panel(cpanel, plesk, etc.)
Actually, its not. WordPress database backup plugin is a better tool as long as you choose to backup the database manually or by automatic server backups. But if you want to automatically create and download the backup dumps to your system, you want Remote Database Backup plugin. I have created a script that will do this automatically for you.
Depends on what kind of blog you have. If you post frequently and have a lot of commenting going on, you will need to backup more frequently than a slower site.
A folder named "backup-(random string)" is created in the wp-content directory to store backups. The 'random string' part of the name is different for different systems. Nefarious types who have a decent idea of the name of the db server, and the database, may be able to remotely load the gz file by guessing the timestamp that forms the final part of the backup file name, or by guessing the entire string correctly. Admittedly a long shot, and the reward is only an encrypted admin password, besides all the contents of your blog.
If you are the paranoid type, delete the backups from the folder asap following download - this will prevent others from getting hands on your database dump.