> io.js is an npm compatible platform originally based on node.js
It's not a library, it's a platform that's based on node.js. It's more or less a fork of node or "spork" as they call it.
The github repo is a bit more clear: https://github.com/iojs/io.js
The main point seems to be that it's run on an open governance model: https://github.com/iojs/io.js/blob/v1.x/GOVERNANCE.md
"io.js is an api-compatible alternative to the node.js runtime, including support for the npm ecosystem, that aims to release faster than the node.js release cycle and move according to a community-driven open governance model."
Given the tremendous volume of packages released to npm, the current one-liner initially just doesn't convey much information. In context of the comments here, it all parses perfectly, but I was one of many who needed this context to understand the (apparent) goals of the project.
Ya, I think the main problem is that no one has any idea what that means from a practical sense. Will my code go faster? Will I get better support? etc.
In Node.js to use ES6 you would have to use the --harmony flag to enable them because the version of V8 that is used is so old. Whereas in Io.js anything V8 deems stable is available in Io.js without having to use the --harmony flag.