flesh out readme, add license

LICENSE.md

@@ -0,0 +1,21 @@
+The MIT License (MIT)
+
+Copyright (c) 2015 [these people](https://github.com/rollup/rollup/graphs/contributors)
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in
+all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+THE SOFTWARE.

README.md

@@ -5,19 +5,81 @@
 > *I roll up, I roll up, I roll up*
 > –[Wiz Khalifa](https://www.youtube.com/watch?v=UhQz-0QVmQ0)
 
+
 ## Quickstart
 
 Rollup can be used via a [JavaScript API](https://github.com/rollup/rollup/wiki/JavaScript-API) or a [Command Line Interface](https://github.com/rollup/rollup/wiki/Command-Line-Interface). Install with `npm install -g rollup` and run `rollup --help` to get started.
 
+[Dive into the wiki](https://github.com/rollup/rollup/wiki) when you're ready to learn more about Rollup and ES6 modules.
+
+
 ## A next-generation ES6 module bundler
 
 When you're developing software, it's much easier to break your library or application apart into separate pieces that you can work on separately. It's also very likely that you'll have dependencies on third party libraries. The result is lots of small files – but that's bad news for browsers, which get slowed down by having to make many requests.
 
-The solution is to bundle your code into a single file that includes everything you need.
+The solution is to write you code as **modules**, and use a **module bundler** to concatenate everything into a single file. [Browserify](http://browserify.org/) and [Webpack](http://webpack.github.io/) are examples of module bundlers.
+
+So far, so good, **but there's a problem**. When you include a library in your bundle...
+
+```
+var utils = require( 'utils' );
+
+var query = 'Rollup';
+utils.ajax( 'https://api.example.com?search=' + query ).then( handleResponse );
+```
+
+...you include the *whole* library, including lots of code you're not actually using.
+
+**ES6 modules solve this problem.** Instead of importing the whole of `utils`, we can just import the `ajax` function we need:
+
+```js
+import { ajax } from 'utils';
+
+var query = 'Rollup';
+ajax( 'https://api.example.com?search=' + query ).then( handleResponse );
+```
+
+Rollup statically analyses your code, and your dependencies, and includes the bare minimum in your bundle.
+
+
+## Shouldn't we be writing those utilities as small modules anyway?
+
+[Not always, no.](https://medium.com/@Rich_Harris/small-modules-it-s-not-quite-that-simple-3ca532d65de4)
+
+
+## Don't minifiers already do this?
+
+If you minify code with something like [UglifyJS](https://github.com/mishoo/UglifyJS2) (and you should!) then some unused code will be removed:
+
+```js
+(function () {
+  function foo () {
+    console.log( 'this function was included!' );
+  }
+
+  function bar () {
+    console.log( 'this function was not' );
+    baz();
+  }
+
+  function baz () {
+    console.log( 'neither was this' );
+  }
+
+  foo();
+})();
+```
+
+A minifier can detect that `foo` gets called, but that `bar` doesn't. When we remove `bar`, it turns out that we can also remove `baz`.
+
+Unfortunately, **traditional modules – CommonJS and AMD – make this kind of optimisation next to impossible**. Rather than *excluding dead code*, we should be *including live code*. That's only possible with ES6 modules.
+
 
-TKTKTKTK browserify, webpack, yada yada
+## What's the catch?
 
+Most libraries that you depend on aren't written as ES6 modules, so Rollup can't work with them directly. (You *can* bundle your own app or library code with Rollup as a CommonJS module, then pass the result over to Webpack or Browserify, of course.)
 
+**You can help!** It's possible to write libraries as ES6 modules while still making it easy for other developers to use your code as they already do, using the [jsnext:main](https://github.com/rollup/rollup/wiki/jsnext:main) field in your package.json. You'll be writing your code in a more future-proof way, and helping to bring an end to the [dark days of JavaScript package management](https://medium.com/@trek/last-week-i-had-a-small-meltdown-on-twitter-about-npms-future-plans-around-front-end-packaging-b424dd8d367a).
 
 
 ## License