Next year, if all goes according to plan, Red Hat will become the first open source software company to generate more than US$1 billion a year in revenue. It will be a watershed moment for the open source community, who have long seen their approach of community-based development as a viable, even superior, alternative to traditional notions of how software should be written.

"I think we're seeing a fundamental shift in where innovation happens, going from the labs of a few software companies to these massive open source efforts," said Jim Whitehurst, president and CEO of Red Hat.

Certainly, open source has left the proprietary software world in turmoil over the past few years, as Linux, the Apache Web server, Perl, Apache, Hadoop, OpenOffice, GIMP and dozens of other programs put the pinch on their commercial counterparts. But what are tomorrow's open source heavy hitters? Here are five projects to watch closely in 2012. They may form the basis for new businesses and new industries. Or they may just capture the minds of developers and administrators with some easier, or at least less expensive, way of getting the job done.

Nginx

For the better part of the last decade, the choice for Web server software has been pretty stable. Apache has been used on the majority of Web servers while Microsoft's IIS (Internet Information Services) is used across many of the rest. Over the past few years, however, use of a third entrant, Nginx (pronounced "engine-x"), has been on the rise, thanks to the software's ability to easily handle high-volume traffic.

Nginx is already run on 50 million different Internet domains, or about 10 percent of the entire Internet, the developers of the software estimate. It is particularly widely used on highly trafficked Web sites, such as Facebook, Zappos, Groupon, Hulu, Dropbox, and WordPress. Not surprisingly, the software's creator, Igor Sysoev, designed Nginx in 2004 specifically to handle a large numbers of concurrent users -- up to 10,000 connections per server. "It is a very lean architecture," said Andrew Alexeev, a co-founder of a company that offers a commercial version of the software, called Nginx.

The upcoming year promises to be a good one for Nginx. Last year, Nginx got $3 million in backing from a number of venture capital firms, including one supported by Dell CEO Michael Dell. It partnered with Jet-Stream to provide Nginx for that software vendor's CDN (content delivery network) package. It also is working with Amazon to streamline Nginx for the AWS (Amazon Web Service) cloud service.

Beyond Nginx's use in large Web operations, Alexeev sees wider use for Nginx in the emerging cloud computing and shared services market. "This is where we can add the most benefit," Alexeev said. The next major release of the software, due next year, will be more pliable for shared hosting environments. It will be better able to handle DDoS (Distributed Denial of Service Attacks), and come with additional security features, he said.

OpenStack

The OpenStack project arrived relatively late to the cloud computing party, but it comes with one particularly indispensable feature: scalability.

"We're not talking about [using OpenStack to run a] cloud of 100 servers or even 1,000 servers, but tens of thousands of servers. Other options out there aren't really considering that scale," said Jonathan Bryce, chairman of the OpenStack Project Policy Board.

Since its launch in July 2010, OpenStack quickly gained a great deal of support from IT firms interested in the cloud computing space, such as Hewlett-Packard, Intel and Dell. OpenStack devotees like to call their work the fastest growing open source project, with involvement from over 144 companies and 2,100 participants. Dell launched a package, called the Dell OpenStack Cloud Solution, which combines OpenStack with the company's own servers and software. HP launched a beta public cloud service with the technology as well.

The core computational components of OpenStack were developed at NASA Ames Research Center, for an internal cloud to store large amounts of space imagery. Originally, the NASA administrators tried using the Eucalyptus software project platform, but found challenges in scaling the software to the required levels, according to Chris Kemp, who oversaw the development of the OpenStack cloud controller when he was CIO of NASA Ames.

To aid in wider adoption, OpenStack is being outfitted with a number of new features that should make it more palatable for enterprises, said John Engates, chief technology officer for managed hosting provider Rackspace. One project, called Keystone, will allow organizations to integrate OpenStack with their identity management systems, those based on Microsoft Active Directory or other LDAP (Lightweight Directory Access Protocol) implementations. Also, developers are working on a front-end portal for the software as well. Rackspace, which first partnered with NASA to package OpenStack for general usage, is also spinning off the project as a fully independent stand-alone entity, in hopes that it will be an attractive option for more cloud providers.

"2011 was the year for building the base of the product, but I think 2012 is where we really start to use that base for a lot of private and public clouds," Engates said.

Stig

The past year has seen the dramatic growth in the use of nonrelational databases, such as Cassandra, MongoDB, CouchDB and countless others. But at the NoSQL Now conference, held last September, much of the buzz surrounded a still unreleased data store called Stig. With any luck, we will see Stig in 2012.

Stig is designed for the unique workloads of social networking sites, its maintainers claim. It was created at the social networking site Tagged by software engineer Jason Lucas, who calls the technology a distributed graph database. It is designed to support heavily interactive and social Web applications. The data store's architecture allows for inferential searching, allowing users and applications to look for connections between disparate pieces of information. Because it was written, in part, in the Haskell functional programming language, it can easily divide up its workload across multiple servers.

Stig is still a bit of a mystery, as it hasn't been actually released yet. But observers are predicting it could fit a niche in the social networks and other applications that keep a wide range of data. The needs of social networking services are inherently different from other types of jobs, and would benefit from a database attuned to its needs, Lucas explained. "You can't be a relevant service in this space without being able to scale to a planetary size," he said.

Stig is currently operating on one server at Tagged, though the company expects to expand its use to the point where it will be the sole database for the company. Originally, the developers were planning to source code by December, but moved back the release to sometime in 2012.

"What I did see looked very interesting," said Dan McCreary, a semantic solutions architect for the Kelly-McCreary & Associates consulting firm. He praised the database's functional language architecture, which should ease the deployment of the database across multiple servers.

Linux Mint

Despite years of advocacy on the part of open source adherents, Linux has never had a strong presence on the desktop. But usually there is always one user-friendly Linux distribution to use, as an alternative to Microsoft Windows. In recent years, Canonical's Ubuntu has fulfilled this role, though the increasingly popular Linux Mint may trump Ubuntu by being even easier to use.

Software engineer Clement Lefebvre first crafted Linux Mint after a gig of reviewing other Linux distributions for various online forums. From this work, Lefebvre developed ideas about what features should be in the ideal distribution. Just as Canonical appropriated the Debian Linux distribution for its own massively popular Ubuntu, Lefebvre used Ubuntu as the base for Linux Mint. Today, the Linux Mint project is funded by donations, advertising revenue from its Web site, and income derived from user searches, the last through a controversial partnership with DuckDuckGo.

Linux Mint is designed specifically for people who just want a desktop OS, and who don't wish to learn more about how Linux works (i.e. non-Linux hobbyists). This approach makes installing and running the software easy and maintenance pretty much a nonissue. Even more than Ubuntu, Mint emphasizes easy usability, at the expense of not using new features until they have proven themselves trustworthy.

For instance, Mint eschews the somewhat controversial Unity desktop interface, which Canonical adopted to more easily port Ubuntu to mobile platforms. Instead, Mint sticks with the more widely known, and more mature, Gnome interface.

Such rigorous adherence to usability may be helping Linux Mint, much to the detriment of Ubuntu, in fact. The Linux Mint project claims its OS is now the fourth most widely used desktop OS in the world, after Windows, Apple Mac and Ubuntu. Over the past year, Mint has even usurped Ubuntu as the distribution that generates the most page views on the DistroWatch Linux news site, a metric generally thought to reflect the popularity of Linux distributions. No doubt 2012 will see only more growth for the OS.

Gluster

Could Red Hat revolutionize the world of storage software in much the same way it revolutionized the market for Unix-based OSes? In October, Red Hat purchased Gluster, which, with its GlusterFS file system, makes open source software that clusters commodity SATA (Serial Advanced Technology Attachment) drives and NAS (network attached storage) systems into massively scalable pools of storage. Red Hat plans to apply the method it used to dominate the market for Linux OSes for the storage space as well.

According to Red Hat's Whitehurst, the storage software market generates $4 billion in revenue annually, though that's not why the company was interested in the technology. Instead, Red Hat was interested in finding a storage technology that would make cloud migrations easier. "We look for places where open source would be particularly powerful as a way to innovate, and we look for areas in the stack where we think we can monetize," he said. "There are not other solutions like that out there."

The software has some momentum, at least in terms of administrators downloading and testing the software. Over the past year, GlusterFS downloads increased by 300 percent. In November, the software was downloaded over 37,000 times.

Joab Jackson covers enterprise software and general technology breaking news for The IDG News Service. Follow Joab on Twitter at @Joab_Jackson. Joab's e-mail address is Joab_Jackson@idg.com