RSS is a good tool. It gives you a simple way to shape and filter the web’s content to suit your own needs. It lends you its power when you need it without requiring any broader entanglement. Its developers, to their credit, made its simplicity central. They were acting as tool-makers, which is how software programmers and web developers tended to act a decade ago. That was before the platform-builders arrived, with their schemes.

Google was once a tool-maker. Now, it’s a platform-builder. Like Facebook. Like Apple. Like Microsoft. Like Twitter. Like all the rest. And so Google is killing off its popular RSS tool Google Reader. Tools are threats to platforms because they give their owners ways to bypass platforms. If you have a good set of tools, you don’t need a stinking platform. If you’re happy with RSS, you’re a little less likely to sign up for Google or Twitter or Facebook. At the very least, the tool gives you the choice. It grants you self-determination.

RSS, like other web tools and even other personal-computer tools, is doomed—not doomed, necessarily, to disappear, but doomed to be on the periphery, largely out of sight. “We’re living in a new kind of computing environment,” said Google engineer Urs Hölzle in announcing the “closure” of Google Reader. He’s right. The tool environment is gone. The platform environment is here. Consider yourself entangled.