Backbone
Main high-speed network connection composing the Internet. Backbones are operated by major telecommunications companies like Sprint, MCI, or AT&T. In general, the better the backbone of the hosting company, the better the availability of the web sites that run on their computers. Internet backbone maps are here. http://www.nthelp.com/maps.htm
Backups
Web hosts back up data on their servers. Many host packages offer backups every 24 hours. This is supposed to prevent the loss of data should something happen to the server. . If you think you may need to restore old data in case of a disaster, it may make sense to choose a hosting company that performs regular backups.
Bandwidth
The amount of data that can be transmitted at a given moment to a server. The higher your bandwidth, the larger amount of traffic your site can handle at one time.
