Backblaze is an unlimited online backup service for PC and Mac.  It lets you backup all your computer files for as little as $3.96/month.  Founded in 2007, the company now stores over 100 petabytes of customer data.

I’ve been using Backblaze for over a year now, and it has protected my PC the entire time.  Backblaze has changed slightly since my last review, so I’ve re-written it to reflect what I think of it now, in 2014.