add features section

README.md

@@ -19,6 +19,31 @@ This powers PixelProxy, software which has been observed driving 15,000+
 pixels at 40 FPS on a single Raspberry Pi without coming close to hitting
 any hardware constraints.
 
+## Capabilities
+
+**gopushpixels** is a set of Go packages offering a fully-featured PixelPusher
+interface, which can:
+
+*   Passively discover devices and maintain a registry of active devices.
+*   Automatically generate stubs to interact with discovered devices.
+*   Generate, manipulate, and capture pixel buffers.
+*   Efficiently route pixel data to devices by group/controller or ID.
+*   Offers a man-in-the-middle proxy capability, which can:
+    *   Intercept, inspect, record, and modify PixelPusher data.
+    *   Advertise as fake PixelPusher devices, to interface with generation
+        software.
+*   Collect operational metrics using [Prometheus](https://prometheus.io/)
+    client integration.
+*   Support for several hardware devices, configurations, layouts, and software
+    versions.
+*   Facilities to record and replay pixel data.
+*   A low-overhead file format to store pixel data:
+    *   Data can be associated with local or physical devices.
+    *   Smaller files can be merged together.
+    *   Optional compression support.
+*   Perform both generation and parsing of PixelPusher's protocol, allowing
+    simulation of PixelPusher devices.
+
 ## Packages
 
 **gopushpixels** includes a set of core packages, which expose basic device