It’s odd to wake up to hear that one company is suing another to maintain the terms of an expired contract. But that’s exactly what happened to me on Thursday morning, thanks to a post by Andrew Grill, CEO of influence monitoring tool Kred on Google+:

PeopleBrowsr and Twitter appeared in San Francisco Superior Court today. PeopleBrowsr won a restraining order compelling Twitter to provide full Firehose access. The court rejected Twitter’s contention that the application was without merit.

Kred is, of course, powered by PeopleBrowsr’s access to the Firehose – the complete, unfiltered stream of tweets coming over the Twitter network. PeopleBrowsr has given a clear reason for its actions:

“We relied on Twitter’s promise of openness when we invested millions of dollars and thousands of hours of development time,” said Rich. “Long term supply is essential as this industry matures. We made this application to ensure full unrestricted access to the Firehose for our Enterprise and Government clients.”

Ah, there’s the rub. They relied on a commercial company to behave like an open platform. And for all the hype around the social networking “platforms”, they’re only platforms for as long as their owners want them to be. And right now, Twitter clearly wants to be less of a platform than it once was:

PeopleBrowsr and Twitter negotiated, at arm’s length, an integrated contract with a one year term, after which either party could terminate at will after giving 30 days’ notice. Twitter has exercised that contractual right. PeopleBrowsr attempts to ignore the plain language of the contract by imagining completely different contract, arguing that ‘Twitter contracted to provide an open ecosystem.’ … Nonsense.

The Twitter “ecosystem” exists only at the sufferance of Twitter. The microblogging service is a changing beast, and one that is changing in search of a business model. In one sense, this is something Twitter users should celebrate, if they want to keep on using the service. However, a justifiable concern that the service that emerges won’t look much like the one we use now is emerging.

Where once access to that very firehose seemed to be the emerging model, Twitter is now just farming out limited access through three partners – and losing any interest in dealing directly with companies like PeopleBrowsr. Instead, a business model as a media adjunct and advertising channel is opening up. Like the Twitter client developers before them, those who built their business model on Twitter’s previous access conditions are out in the cold.

The social ecosystem that emerged in the early-to-mid 2000s was built in a more open way. Blogging was a platform, but one that supported multiple vendors, each interoperating through a set of common standards, including XML-RPC and AtomPub for API access, the Movable Type and WordPress export formats, which became a common way of swapping your content between systems, RSS and Atom for syndication. You could build a business against one or all of these platforms, with some confidence that if they changed, you could switch to the others..

The late 2000s onwards have seen the emergence of ever simpler ways to engage socially online – but that has come at a cost. You’re no longer using a software type – like forums or blogs – but a site. An owned, commercial entity controls the content – and access to the content. If your build your business on one understanding of their model, and that shifts, you’re out of luck.

Yet, still the rhetoric of “be a platform” and “build on the platform” continued, even as the environment changed. People built business – quite sizeable businesses – on the “platforms” of Facebook and Twitter, and are only now discovering the very palpable difference between distributed platforms and owned ones.

We’ve seen this recently with Facebook. Many companies – particularly those who think of themselves as “brands” – are distressed by the changes that Facebook has brought to Edgerank, its system for determining what people do and don’t see in their news feed. That assumption – unproven – was that Facebook was depriving these brands of access to their fans so they would be forced to advertise instead.

Matthew Ingram identified the core problem with the arguments the annoyed brands were making in a perceptive post for GigaOM:

…this kind of criticism makes little sense, unless you assume that Facebook is supposed to be a utility of some kind, broadcasting the messages of its users far and wide without any kind of filtering whatsoever. The reality is that a proprietary platform like Facebook is very much a double-edged sword, and Cuban and Takei are feeling the sharpness of that alternate edge: yes, it reaches a lot of people, but it is also a business that faces significant financial pressure.

The problem is born of the basic misunderstanding that Facebook and Twitter are open platforms that we can do what we wish with. That simply isn’t true. They’re commercial entities who can and will change their minds

Should you avoid partnering with them? Of course not – they wield so much power online right now that it would be a serious handicap to completely discount them. But equally, if you’re looking to a long-term sustainable business, it feels deeply unwise to tie it completely to any one web property, without some idea of how you transition if your platform not longer feels as stable as it once did. We either need to be a lot more idealistic in the way we build out the social web – and push back harder against the rise of corporate sites – or we need to be more pragmatic in the way we build our businesses in partnership with other commercial interests.

The siren call of the “open platform” has led many a startup off course – and now some of them look like they’re heading straight for the rocks…