As year moves toward a conclusion, it is time for a moment of reflection. Don’t worry this won’t involve any ghosts waking you from your eggnog fueled holiday slumber. We simply look back at the top five events of 2010 that were most meaningful in open source and will continue to influence the market in 2011 and beyond.

1. The First Billion-Dollar Open Source Company

Adopting an open source operating system, especially for enterprise class use, is not without its problems. Many open source projects lack documentation, support, graphical administration tools and packaged installations common with commercial products. Red Hat (news, site) helps organizations close the gaps. Red Hat earned its fortune providing subscription services for support and distribution of Linux.

At the current rate, Red Hat will reach US$ 1 billion in annual revenue in 2011. Only a few software companies, and certainly no open source entities, have reached this milestone. The growth of Red Hat shows it’s not just techies and risk-taking start-ups leveraging open source; adoption has clearly reached the mainstream.

Who says open source can’t make money?

2. Oracle Takes Command

Oracle (news, site) completed its acquisition of Sun (news, site) in January of this year. With the acquisition, Oracle acquired Sun’s catalog of open source projects, most notably Java. Oracle may think its business runs on open source, but the open source community seems to be running away from the software behemoth.

In August, Oracle sued Google for copyright and patent infringement. Oracle claimed that Google’s Android is illegally using ideas and code from Java. After ten years of being a very visible member of the Java Community Process, Apache resigned from JCP's Executive Committee in December. The company’s frustration finally peaked at Oracle’s refusal to certify Apache’s open source Java runtime Harmony. The debacle goes back to 2006 when Sun was involved.

Java isn’t the only open source technology feeling Oracle’s embrace. There are rumors that Sun wants to revert Solaris, or at least parts of it, to being proprietary. The OpenOffice community formed the Document Foundation, forked from the main OpenOffice project and released LibreOffice fearing the impact of assimilation into Oracle.

The Hudson project, an open source continuous integration server, has been forbidden to use the Hudson name if developers elect to host the project on GitHub instead of Java.net. Officially however, Oracle does not have a trademark on the product.

3. The Rise of NoSQL

With popularity bolstered by web companies like Facebook, Google and Amazon, many companies gave NoSQL more than a cursory look in 2010.  Cassandra displaced MySQL at Twitter and became the primary information sorting system at  Digg. NoSQL providers users the promise of cheap, fast and highly available data storage – a pretty compelling value proposition given the rate of data growth some organizations are experiencing.

And, according to some companies like CouchOne (news, site), which has taken NoSQL mobile, NoSQL isn’t just for internet scale data. NoSQL databases provide other benefits out of the box like high availability, high performance on commodity hardware and replication that make the technology attractive for everyday usage and storage in the cloud. Similar capabilities in commercial products are expensive and extremely difficult to implement.

Although NoSQL walked into the spot light in 2010, many technology leaders still aren’t familiar with the technology. Most NoSQL solutions are less than four years old, which makes finding skilled resources to architect and support solutions challenging for most organizations. Further, many in the industry have begun to turn their back on the NoSQL moniker entirely. Despite the challenges, 2010 showed us the promise of this technology couldn’t be ignored or denied. In 2011, we will see this market continue to grow and mature because the need for solutions to manage ballooning Web 2.0 and Web 3.0 data isn’t going anywhere.

4. The Cloud Continues to Float Forward

In 2010, the cloud -- instead of being a nebulous term whispered by technologists in cubicles -- became a part of business strategies and Microsoft (news, site) commercials. Virtually every technology venture, including open source, has a cloud strategy, and according to IDC, the market will be worth over US$ 55 billion - yes billion with a 'B' - by 2014. Cloud computing is giving many open source projects access to complex infrastructure they could never afford to build independently.

In 2010, Microsoft attempted to become a leader in cloud computing with Azure, its platform as a service offering released in Febuary. Competing directly with Amazon EC2 (news, site), and the likes of IBM, Cisco Systems, EMC Corp., VMware and Rackspace, the Seattle giant release an aggressive Windows Azure road map and changed its pricing model to offer extra small instances similar to Amazon's micro instances.

Microsoft wasn't the only company working on its cloud credibility in 2010. In 2009, Oracle's  Larry Ellison denounced cloud computing as "absurdity" and "idiocy", backed by "nitwit" venture capitalists. Oh, what a difference a year makes. At this year's Oracle OpenWorld, Ellison changed direction to announce Oracle would be a cloud vendor.

2010 also brought Google’s cloud-based operating system -- the Chrome OS. Salesforce introduced Chatter, a social networking tool for its popular cloud platform; the company also made moves to support development in Ruby. VMWare, known for its strength in virtualized infrastructure, went even more virtual and has begun to treat virtual machines as resources that may be located on premises or in a public cloud.

This year demonstrated that cloud computing isn't floating away anytime soon.

5. Microsoft Opens Up

For years, Microsoft has been seen as nothing less than a fierce enemy to the open source community. Perhaps, the software company is softening with age, as in addition to Microsoft backed sites Port25 and CodePlex, Microsoft has contributed 20,000 lines of device driver code to the Linux kernel so Linux can run on Hyper-V. Their IIS web platform installer features 23 open source applications out of a total of 25.  The also certified its first open source application on the Windows Server 2008 R2 platform.

With 20% of the software market represented by open source, learning to play nice is probably a good idea. Well played Microsoft, well played.

What do you think was most significant in the open source market in 2010?