Within a single SpiderOak account, you may use the SpiderOak application on as many computers as you would like, backing up as much or as little data as you need. SpiderOak also supports selecting external hard drives, removable devices, and network volumes for backup.
SpiderOak's goal is to provide a central place to safely and securely back up and store all your data, regardless of what computer, hardware, or operating system it exists on.
SpiderOak simply charges for the amount of storage you actually use, and SpiderOak's intensive compression and de-duplication ensures your data uses the least possible space within your SpiderOak account.
To make our pricing structure more competitive, SpiderOak does intense compression and de-duplication within a backup set (even across multiple computers). Whenever new data is stored, SpiderOak tries hard to store it in terms of references to existing data blocks. SpiderOak is therefore able to retain all previous versions of files using very little extra space. Any duplicated data between however many computers you backup with SpiderOak does not take any extra space. We have customers who have stored hundreds of gigabytes of user data within a 100 GB SpiderOak account.