Update README.md with comparison to JSON.

README.md

@@ -0,0 +1,40 @@
+# arson, _n_.
+> the criminal act of deliberately setting fire to property
+
+### *AR*bitrary *S*tructured *O*bject *N*otation
+
+JSON is great until you need to encode an object with circular references:
+```js
+var obj = {};
+obj.self = obj;
+JSON.stringify(obj); // throws
+```
+
+Throwing an exception is lame, but even worse is muddling along as if everything is ok:
+```js
+var a = {};
+var b = { foo: 42 };
+a.x = a.y = b;
+var c = JSON.parse(JSON.stringify(a));
+assert.strictEqual(c.x, c.y); // fails
+```
+
+We need an object notation that supports circular and repeated references.
+
+That's where `ARSON` comes in:
+```js
+var a = {};
+var b = { foo: 42 };
+a.x = a.y = b;
+var c = ARSON.parse(ARSON.stringify(a));
+assert.strictEqual(c.x, c.y); // no problem!
+```
+
+`ARSON` is compact, often even more compact than JSON, because repeated objects are defined only once:
+```js
+var a = {};
+var b = { foo: 42 };
+a.x = a.y = b;
+ARSON.stringify(a); // [{"x":1,"y":1},{"foo":2},42] vs.
+ // {"x":{"foo":42},"y":{"foo":42}}
+```