Not necessarily. I was introduced to Dropbox at a computer security competition a year ago, and I’ve really liked it, but I haven’t really taken the plunge in terms of storing my important data on it. Sure, Dropbox sports encryption, but that doesn’t protect me from Big Brother giving Dropbox a subpoena. The solution I chose to solve that problem was to use a encrypted filesystem and store my files inside of it on Dropbox. This way, Dropbox admins can’t read my files, and nor can people that could steal my laptop/PC/whatever.
The cool thing is: Dropbox is supported on Win/Mac/Linux, and so is EncFS(For Windows, support is somewhat limited) So, now I have 2 GB of data nestled on the cloud tightly secured for free.
https://www.dropbox.com/ (all platforms)
http://www.arg0.net/encfs (Should find this in your distro)