Today, Facebook joins Twitter in generating discussion, angry words, and hurt feelings around application-platform ecosystems. Mathew Ingram wonders, is platform Darwinism just the way things work? The short answer is yes. But platform providers have to bring things to the party for developers – and ultimately for users, too – to ensure that the ecosystem thrives. Key ingredients include access to a big or desirable audience and/or data, technologies and support, distribution and a revenue stream to tap into. Facebook’s App Center addressed a bit of its discovery lacks, and though Zynga’s struggling a bit, it’s still generating growing revenues for Facebook (up 10 percent in Q2, even if it’s down as a percentage of Facebook’s total) and for itself. So far, Google+ doesn’t have much to offer to entice developers away from Facebook or Twitter.