Dave Winer has a post entitled How basic is Twitter? where he writes

So inevitably, a query about the value of namespaces leads you to wonder if there will be TwitterClones, web-based services that emulate the Twitter API, that keep internal data structures similar to Twitter, and most important, peer with Twitter, the same way Twitter peers with IM and SMS systems.

This is as far as I got in my thinking when last night I decided to ask Les Orchard, a developer I know for quite a few years, and who I've worked with on a couple of projects, both of which use the kind of technology that would be required for such a project --

What if there were an open source implementation of Twitter?

Nik Cubrilovic happened to be online at the moment and he jumped in with an idea. Les confessed that he was thinking of doing such a project. I thought to myself that there must be a lot of developers thinking about this right about now. We agreed it was an interesting question, and I said I'd write it up on Scripting News, which is what I'm doing right now.

What do you think? Is Twitter important, like web servers, or blogging software, so important that we should have an open source implementation of something that works like Twitter and can connect up to Twitter? Where are the tough sub-projects, and how much does it depend on the willingness of the developers of Twitter #1 to support systems that connect to theirs?

The problem I see here is that Twitter isn't like web servers or a blogging engine because Twitter is social software. Specifically, the value of Twitter to its users is less about its functionality and more about the fact that their friends use it. This is the same as it is for other kinds of social/communications software like Facebook or Windows Live Messenger. Features are what gets the initial users in the door but it's the social network that keeps them there. This is a classic example of how social software is the new vendor lock-in.

So what does this have to do with Open Source? Lots. One of the primary benefits to customers of using Open Source software is that it denies vendor lock-in because the source code is available and freely redistributable. This is a strong benefit when the source code is physically distributed to the user either as desktop software or as server software that the user installs. In both these cases, any shabby behavior on the part of the vendor can lead to a code fork or at the very least users can take matters into their own hands and improve the software to their liking.   

Things are different on the "Web 2.0" world of social software for two reasons. The obvious one being that the software isn't physically distributed to the users but the less obvious reason is that social software depends on network effects. The more users you have, the more valuable the site is to each user. Having access to Slashcode didn't cause the social lock-in that Slashdot had on geek news sites to end. That site was only overtaken when a new service that harnessed network effects better than they did showed up on the scene (i.e. Digg). Similarly, how much value do you think there is to be had from a snapshot of the source code for eBay or Facebook being made available? This is one area where Open Source offers no solution to the problem of vendor lock-in. In addition, the fact that we are increasingly moving to a Web-based world means that Open Source will be less and less effective as a mechanism for preventing vendor-lockin in the software industry. This is why Open Source is dead, as it will cease to be relevant in a world where most consumers of software actually use services as opposed to installing and maintaining software that is "distributed" to them.  

Granted, I have no idea why Dave Winer would like to build an Open Source competitor to Twitter. The main thing that will come out of it is that it will make it easier for people to build Twitter knock offs. However given how easy it is to roll your own knock off of popular "Web 2.0" social sites (e.g. 23, SuperGu, Uncut, etc) this doesn't seem like a lofty goal in itself. I'm curious as to where Dave is going with this since he often has good insights that aren't obvious at first blush.