- Encrypted; strong encryption available too (free)
- Peer-to-peer backup is free forever: backup to your friends' house across town or the state
- Windows/Mac/Linux can all backup to each other
- Backup size is limited only by storage available
- Multiple retention periods are customizable (hourly/daily/weekly/monthly/yearly)
- Pruning happens automatically
- Block-level deduplication and compression
- Backup any folders/files on any drives on your system (can specify files within a folder or a whole folder, so newly added files automatically back up)
If you are backing up in your house, good job. But if your house burns down or otherwise destroyed, chances are your main computer and backup are gone. Back up to a geographically separated location and your chances of being able to recover important or one-of-a-kind files increases dramatically. For around $100, you can get a 3TB USB 3 external HD. For most people, that drive size will last a really long time.
If you want to use the CrashPlan central service, you can restore files anywhere you have a browser and to any computer. That makes it a bit like Dropbox, but it for any files you have in your backup set.
If anyone would like to try out, or heck, just use my server for their backups from now on, PM me your email address and I'll send you an invite. I've only got about 4TB of space left...