Creates a Snapshot Backup of your entire website and uploads it to an FTP repository.
Archiving dynamic websites isn't all that easy and we all tend to forget that because the web is such a fluid thing. The idea of Snapshot is that you may want to create an 'as is' version of your website for archive purposes. With each click you'll create a time capsule of sorts - this could be for legal, sentimental or security reasons.
Other solutions mirror your or snyc your installation. This is a great idea too, however if you only notice a week down the line that your site has been compromised then your synced copy most certainly is too. Snapshot makes it easy to go back to a clean version from x days/weeks/months ago.