Carbonite's upgrades come in two flavors: Home Plus and Home Premier. Home Plus offers the traditional online backup to Carbonite's data centers, plus automated local backup to an external hard drive. Home Premier offers not only data backup but also keeps a full copy of applications and operating systems for full-system restores.

"If your hard drive crashes or it gets a virus, you can boot off a recovery CD you can create from our website or boot from the external hard drive," said Tom Murray, vice president of marketing for Carbonite. "This way you can avoid the expense and delay of getting all that foundational information reinstalled on your computer."

Additionally, the Home Premier service comes with Courier Recovery, for which Carbonite copies data from its servers onto an external drive and ships it overnight.

"The idea is you might need that data with urgency and with courier recovery we can get you that information faster than streaming it to you online," Murray said.

Carbonite Home has an annual subscription rate of $59. The Home Plus version costs $99 per year and includes unlimited backup protection and external hard drive backup and mirror image. Home Premier, with courier service, sells for $149 per year.