I’ve been seeking cloud storage of my life for long time now. My needs are not much (but most of the time they are too big as I have learned) only space and if possible Linux/Mac OS X FUSE for using service.
Service being open source or not isn’t such big thing in this case. How data is stored (crypted or not) and how can I get them out there if I need them is what I treasure most.
I have tested SpiderOak, Wuala, Dropbox and box.net but non of them fits for my needs perfectly. As I want to use these services with Linux all of them have Linux clients and most of them have FUSE-filesystem. Lately I have been using Wuala but it has problem that FUSE stuff is written in Java (it works under openSUSE just fine!). With GUI it’s clean and like said works very well but then comes but if you don’t want to use GUI you are in little bit trouble. It’s supported but I haven’t got it working. Xvfb comes to rescue but still it’s not really a solution!
When I heard about Elfcloud.fi I though okay we have some storage provider in Finland no big deal. I just popped their web site and noticed that they are really open source friendly company. They have Github Python-library (Apache Version 2.0 licensed) and full API documentation which is dead simple JSON stuff also their pricing scheme ain’t that bad. I have mention that this is hardcore crypto cloud service. If you lose your key you can wave goodbye to you data. Best of all they gonna have marvelous FUSE implementation as I’m writing it currently (They also have C++ library available on request. Apache Version 2.0 licensed of course).
So if you want to keep your data on Europe and have it stored in same country that have also is also trusted by Google datacenters and Microsoft you can check out elfcloud.fi. It’s not for everyone for sure but those who are in same need place to store data without hustle this can be the stuff for you.

You can download python API RPM from here: http://download.opensuse.org/repositories/home:/illuusio:/elfcloud/