I use TrueCrypt on my Dropbox volume, but it really would be nice to have an integrated solution. Many non-technical users may not realize they care about this, but they do.
(I cofounded SpiderOak in 2007)
It's the group in between that is the most interesting to these companies right now. Those who are relatively well informed about major technologies and their uses. Do they really want to have their information mostly stored off-site, or do they simply want larger and larger local storage mirrored by online back-up for peace of mind and easy sharing?
I would guess that this is the largest (apparent)consumer market and one of the reasons why this is where most of these companies have their focus right now.