The website is hosted by a company called dreamhost.com; this is a large ISP witha good reputation for service and support.  They backup their servers nightly and also take 'snapshot' backups of the system.  This is what they say:

 On every DreamHost plan we keep extensive back-ups of your data. Periodically our disk filers take what is known as a "snapshot" of the entire file system as it stands at that time. If you accidentally delete a file you need, contact support, and we'll try and recover the most recent version of it we can! We recommend you always keep your OWN copy of your entire web site at a remote location as well, but we'll do our best to make sure that's never needed. Our filers are completely RAIDed and hot-swappable so if any disk fails no data is lost, and we can replace the disk without any interruption of service! There is no additional cost for these backup features.

 As they state, we should also take copies of the system.  This is especially true if any major changes are to be made to the site.  The following details a step by step guide to site backup.  This is a very detailed guide;  the actual backups will only take a few minutes to perform.

There are two separate parts to the site, the database and the files.  These have to be backed up and restored together to provide a complete backup.