Update README.

README.md

@@ -1,7 +1,7 @@
 Welcome to Log Magic.
 ====================
 
-This project isn't usable yet. No promises.  The Bellow is an idea.
+This project is usable. It doesn't do everything it should, yet.
 
 The goal is to have a fast and easy to use logging subsystem that can be dynamically
 reconfigured to provide insight into production systems.
@@ -17,7 +17,8 @@ If you had a file named like, "lib/foo/bar.js", at the top of it, you would put
 Then inside bar.js, you would just use the logger like any normal logger:
 
     log.info("Hello!")
-    log.error("Accepts format strings too ${SOME_VAR}", {SOME_VAR: "myvalue"})
+    log.error("By default, format strings are not used.", {SOME_VAR: "myvalue"})
+    log.errorf("Just add 'f' to any log method, and you get format strings too: ${SOME_VAR}", {SOME_VAR: "myvalue"})
 
 In any other part of your application, you can reconfigure the logging subsystem at runtime,
 making it easy to change log levels for specific modules dynamically.
@@ -34,7 +35,8 @@ making it easy to change log levels for specific modules dynamically.
 
 Builtin sinks include:
 
-* Standard Error
+* stderr
+* Graylog2-style JSON to stderr
 
 Future features:
 * Standard Out