diff --git a/README.md b/README.md
index e7ae958..9bbe686 100644
--- a/README.md
+++ b/README.md
@@ -1,12 +1,21 @@
 # FRP tools
 
-Observer and computed value stores designed to work together for storing real state and derived
+Observer and Computed value stores designed to work together for storing real state and derived
 state.
 
 # [observable](./src/observable.js)
 
 `observable` is a simple value store that can report when its value changes. It is good for wrapping
-external props passed into a component so compute types can dependent on them.
+external props passed into a component so compute types can dependent on them. It can also be used
+to receive events such as _window.onresize_ to always provide the current viewport size.
+
+NOTE: Javascript has a proposal for a thing called an
+[Observable](https://github.com/tc39/proposal-observable). This is not an implementation of that.
+They do serve similar functions (provide a way to communicate when a value changes) but the tc39
+proposal is more about event input sources and can communicate errors and be extended. This
+implementation is designed to be as small and simple as possible. Extending it is done via
+[Computed] instances depending on them. I may rename `observable` to `property` in a future major
+release to avoid this confusion.
 
 ## Usage