Half a year ago two things came together that reconciled me with cloud computing: A Raspberry Pi, an inexpensive Linux computer than I can run 24/7 at home as it requires very little power and Owncloud, a piece of open source software that lets me, as its name says, run my own cloud services at home. Not trusting web companies to keep my private data safe even before the recent PRISM revelations I could not export my private data to web based companies. So until then, even though it would have been convenient, I didn't synchronize my calendars and address books on different devices and also did not use cloud storage for exchanging files between different devices and to make them available to others. Obviously when I got things working for the first time I was overjoyed. But how has the setup fared in the past 6 months as routine has set in?
Contacts
In short, it has performed beyond my expectations. Address book synchronization between my Android based mobile devices and Owncloud works like a charm. The only glitch I found so far is that when I rename a contact via the Web interface the change is not propagated to my mobiles. If I do the same on a mobile device, however, the change is properly synchronized. Changes in all other fields are synchronized just fine both ways. Since names of contacts usually change very little that's something that can easily be lived with.
Another thing, due to the limited speed of the Raspi is that it takes a while for the pictures of my contacts to show up in the web interface, even for those contacts that I don't have any pictures and thus get a neutral logo. This has the effect that when I just want to quickly go to my contacts on the PC and then change something it takes a bit for the dialog box that pops-up with the contact's information to become editable. This is not a bug but rather a bit of a usability issue and again not something that stands in the way of an otherwise great usability experience.
Calendar
Calendar synchronization has become even more important to me than address book synchronization across Thunderbird/Lightning on the PC and Android based devices. The Owncloud calendar can be used in Thunderbird with or without a local copy. Over time I noticed that when keeping a local copy, Thunderbird refuses at some point to let me delete some entries while I can delete others just fine. I haven't found a pattern in the behavior but it's not a problem in practice as the online mode that just caches information in Thunderbird for times when a connection to the server is not available works without a flaw. The only downside of online mode is that for adding, removing or changing an entry, Thunderbird needs to have a connection to the Owncloud server. Again, only a problem when I'm not connected, which is pretty much only when I'm on a plane. And even then, I can modify the calendar on my mobile device and changes are synchronized back to Owncloud and Thunderbird as soon as connectivity is reestablished.
File Sharing
I use Owncloud's file storage for sharing files between different devices of my own and also to share files that are too big to be included in emails. Individual files or complete directories can be shared with others without the need for an Owncloud account for the person on my server by generating a link that can simply be clicked. Again, this works great in practice.
A feature requests for the future would be for Owncloud show pictures in externally shared directories with the same gallery option as it does when I view them myself or if I share them with another Owncloud user on my sever. Also, when sharing only a single file the download button should be more in the center of the web browser rather than on the top right for users to find it more easily. Nobody's complained to me about it but I find the layout a bit odd. And finally, I'd like to see an option for external sharing that does not only give me a URL that can be used in my home network but in addition a URL that can be used externally. Today I copy/paste the URL to an email and then replace the beginning of the link with my externally visible URL and a different TCP port number. Not a problem for me but normal users struggle a bit with this.
Summary
Yes, I know, there are a lot of other applications for Owncloud but those three are the ones I use on a daily basis. I can't say this often enough, the combination of a Raspi and Owncloud has been a real game changer for me as I now enjoy the benefits of cloud services without the need for putting my private data out of my zone of trust.