Some time ago, I bragged about the encryption at SpiderOak.com. However, after using the service for 7 or 8 months and experiencing constant file bloat, I think I’ll switch from Spider Oak to another product. SpiderOak just seems rather confused, in my opinion, about versioning. New versions of the same file are constantly being backed up as new files. By contrast, in products like
SOS Online Backup, which is also secured at the point of backup on my own laptop…

http://www.sosonlinebackup.com/online-pc-backup/military-grade-security.htm

new versions are NOT counted as separate files in one’s file size maximum. (Though SOS does say they count the BIGGEST version of the file.) They save all versions, forever, but they don’t count multiple versions toward my limit.

SOS has also won the PC Magazine’s Editors’ Choice for 4 years straight, for whatever that’s worth. Highly recommended.