The chief selling point of ownCloud, the open source private cloud storage platform, has been its ability to build a cloud entirely on in-house, behind-the-firewall servers. Now, the company has gone a step further by introducing a feature for live, collaborative document editing. How does it stand up against better known alternatives such as Google Docs? Here's a look.

The editing tool, called ownCloud Documents, is one of the new features in ownCloud version 6.1. It allows ownCloud users to view and edit documents in their ownCloud storage from their browsers. It also supports collaboration that makes it possible not only for other local cloud users, but also for people outside the cloud (who can be invited to edit a document via email) to work on the documents at the same time.

So, it's basically Google Docs, but with one very important difference: In ownCloud Documents, all files remain on private, in-house servers—a feature consistent with the core ownCloud vision of allowing users to build (you guessed it!) their own clouds, on their own networks and hardware. Keeping all data private greatly mitigates the concerns that many enterprises—or individual users—may have about storing documents in public clouds, like Google's (GOOG), where they do not have direct control over their data, and where it might be more susceptible to network eavesdroppers while in transit.

What's also cool, at least if you think the way I do, is that ownCloud Documents plays nicely with desktop office applications, like LibreOffice and Microsoft (MSFT) Word. That means you can open and edit documents in your private, ownCloud-based cloud in standalone applications and the broswer at the same time. ownCloud doesn't force you to use the Web interface the way Google Docs does.

Additionally, Free Software fans will be happy to know that ownCloud Documents, like most of the ownCloud platform, is entirely open source. According to ownCloud: "All the code is completely free software. The PHP and the JS components are released under the AGPL license. This is different than most other solutions. Some of them claim to be open source but use creative commons as a code license, which is not free software."