It would be hard to deny that open source has changed enterprise computing in a big way. Linux, MySQL, PHP and a slew of other tools have allowed companies to test ideas and implement solutions at a fraction of the cost of some closed-commercial software.

Right now however, it is mostly commercial vendors creating enterprise social software products, both as on-premise and SaaS based services. Innovation and thought is being driven almost entirely by these vendor, and while that is healthy, we also need to consider the opportunities for Open Source to play a role.

So, what’s next for Open Source in the enterprise? Specifically, what’s next for Open Source and Social Software?

I was watching Fred Wilson talking about the next layer of the social software stack. He says it is Aggregation and Filtering.

I think he is right, and that same thinking extends out of social software and it applies to open source as well. Right now there is an open source alternative for almost any commercial enterprise social software application. In fact, there are usually more and better open source solutions. What is missing however is the ability to aggregate and filter the things we are creating in those tools, inside the firewall.

The Economist says that Open Source has “won the argument” but that it must now find its way in a world where Cloud Computing is becoming a dominate force. This is another example of the many challenges ahead for Open Source.

What we don’t have is an open source suite of tools which can not only be an effective alternative to closed source social software for the enterprise, but can be effectively aggregated and filtered to create an entirely new, and better, experience.

We need an Open Source Social Business Stack which can serve as a foundation to help companies get started with social software, much in the same way the LAMP stack makes development cheaper, a social stack need to provide a set of software which, when aggregated together, create a complete solution.

We have seen SLATES and FLATNESSES, which I believe are great frameworks for defining the elements of enterprise social software. The stack I have been working with is similar in it’s approach to SLATES and FLATNESSES, but it is meant to be more of a deployment-ready stack of enterprise open source social software.

If we break out the stack, I believe that the tools necessary to deploy a foundation of enterprise social software fall in to 4 categories and 2 more general buckets.

Community is the result of a strong set of Profiles and Collaboration tools. The ability to Measure results and effectively calculate ROI comes from building Streams, Filters and Intelligence tools.

This stack provides a foundation to socialize and redefine existing business processes. Like a development stack, these tools will need to be open and interoperable in order to be effective.

So, can Open Source play a role in the future of enterprise social software, or should everyone sit back and wait for the large vendors to provide all the answers? I believe that open source can put renewed momentum behind social tools in the enterprise. To see how close we are, I tried to put together an ideal open source stack.

This is not meant to be an exhaustive list, and it is a work in progress, but I think it identifies some of the best available open source tools to get you started deploying enterprise social tools.

Wikis have been leaders in both the Enterprise and Open Source worlds for a long time. Collaboration tools such as PBwiki (now PBWorks) and Deki Wiki are two of the best enterprise wikis available, and they are open source. MediaWiki, the software that runs Wikipedia, is also open source.

Buddypress is one of the most interesting new projects this year. They are developing an open source community, profiles and blogging platform that I think will change community software the way Wordpress (Buddypress’ parent project) has changed blogging. Buddypress also includes a great streaming and filtering capability called “The Wire”, which seems to be evolving in definition and specification. Lovdbyless is another community platform project to watch. Both of these will be extremely powerful when used inside the firewall.

Jboss Portal Server and Liferay are two of the biggest enterprise open source stories, and their filtering and intelligence capability will be a powerful tool when combined with the other elements of a complete stack.

Finally, Noserub is a stream aggregation engine which can be used to centralize enterprise events and activity, much like a Friendfeed for the enterprise. It would need a lot of customization however, but it is a start. Laconica is the best available micro-messaging tool and it is giving the commercial SaaS vendors a viable alternative. Jive’s OpenFire and eJabberd are two of the best, and most easily integrated, enterprise instant messaging servers out there and offer a potentially powerful integration platform through which enterprise users could intact with, or get information from, other enterprise tools.

These filtering and aggregation tools are crucial because they allow us to knit the stack together, instead of deploying a small set of isolated tools.

What am I missing? What other tools do you think need to be included in a foundational stack to get organizations up and running? I have created a Google Spreadsheet here where you can add entries and help me build a list of Open Source Enterprise 2.0 tools.

The next step is to find some integration points for these tools. Noserub could be a great starting point for integration, or a solid open source RSS reader might be a good start as well.

Please head on over and feel free to add categories, edit entries and help keep things up to date.