Back in the late 1990s there were countless software vendors who realized just how dicey building on top of Microsoft’s platform was. The company was found guilty of antitrust for a reason.

When “The Simpsons” do a parody where Bill Gates comes to “buy out” Homer’s Internet company, and said buy-out is some goons smashing his computer, it’s a safe bet that you’re not exactly considered a friendly business partner.

But by 2007 the memories of that were washed away. That’s when Facebook opened up its platform to third party developers and launched a Valley-wide obsession with all things “platform”. It was mostly reflective of the Valley’s polarization between companies who raised hundreds of millions to become massive tech giants and everyone else wanting to flip.

For the giants: They needed armies of developers making their product even more relevant to the world. For the flippers: It gave them a quick and cheap way to get massive distribution, a built-in way to easily charge users (in the case of the Apple store) and skirt the challenge of having people create a log-in and password for your fledgling Web product (in the case of Facebook and Twitter). For both sides, though, the major benefit was distribution.

It’s not unlike how publishers embraced the shameless laws of SEO to get more page views out of Google. That all seemed great. For a while. And then as those page views became more meaningless, and Google became a swamp of SEO results, old media started bitching about how Google had actually killed their business.

I’m expecting bitching about platforms to start anytime now. Actually it’s already starting. So I’m expecting it to intensify. Witness three recent developments among the three biggest platforms.

1. Twitter Was Epicly Down Today. It’s so down that the error page can’t even say why or when it’ll be up. Instead it shows this:

Bear in mind, this is the day before the 2012 Olympics Opening Ceremony, which should be one of the biggest days of the year for Twitter. Mass media, not to mention all those Olympics apps that blogs have been writing about, are depending on the service to spread the word. The company has to be extremely nervous right now.

Aside from relying on Twitter for distribution, there are an alarming number of companies who are heavily (or completely) relying on Twitter to create their content — including some I love, like RebelMouse, as well as others I would like to love, like Klout. These companies are essentially repackaging Tweets, RTs, and follower counts in new ways. Is that possibly sustainable? This seems all the more dicey, considering reports that Twitter has become increasingly hostile to its developer ecosystem.

This is to say nothing of Twitter’s own uncertain future. Dump on Facebook all you want, thanks to billions in the bank, 1 billion people on its site, and a dual class share structure, its future is pretty assured. In the grand scheme of things, today’s drama over earnings will be just that — drama. But what ultimately happens to Twitter is far less certain. It’s priced out of an acquisition at this point — save an acquisition that’s a huge climb down in terms of valuation. That means the pressure is on to build a huge company. Over the next few years, Twitter will be focused on that, not how developers feel.

2. Zynga’s Wednesday Meltdown. Facebook and Zynga have not always had the friendliest of relationships, but Facebook desperately needs Zynga to do well. Not only does Zynga make up some 15 percent of Facebook’s revenues, but it’s the company every investor and developer is watching to see if you can actually build a huge company on Facebook’s platform.

And Zynga is clearly suffering. As we discussed last week at PandoMonthly with Zynga CEO Mark Pincus, Zynga has to succeed off Facebook — with its own platform and with mobile — if it’s going to get through this trough of investor anger.

3. The Ripple Effects of the Obsession with App Store Rankings. Nathaniel Mott did a great piece for us yesterday on the dramatic impact that the Apple ecosystem is having on software pricing. His post underscored for me how different Apple’s ecosystem has turned out from what I, and others, expected.

Being a content creator, I always saw mobile as sort of a “digital do-over” where we could actually charge for content again. There wasn’t an expectation that everything would be free, and there was an easy mechanism for payment — even if Apple takes a healthy chunk for the convenience. That’s essentially the underpinning behind Paul Carr’s newly launched NSFW Corp.

Roger McNamee echoed as much when he described Apple as the savior for content creators, long squashed by the commoditization of the Google search engine.

Nathaniel paints a very different story, one of software creators who are so desperate for a higher app store ranking that they must slash prices for their creations. That sounds uncomfortably close to the world that McNamee and so many others hoped Apple was delivering us from.

I’m not suggesting you can’t build great businesses on top of platforms. But for too long, developers have considered them a Pleasure Island of distribution without strings. Those things on your arms and legs? Those are strings, Pinocchio.