I've never quite understood the point of using online backup services:

1. The data is transferred to a 3rd party with unknown/unverified privacy controls
2. It is relatively slow to backup data via the internet
3. Who has only 2gb of valuable files?
4. How do you know the backup company is going to exist in X years?

I use my own website for temporary file storage and even for files that I need to access multiple times from multiple computers. But I would never consider putting my secure data out on the net for who knows who to access. Even encrypted I would still be concerned.

Does anyone find online backup services useful? If so, what purpose do you use it for and why do you like it verses the alternatives?