docs: clarify process.stdin and old mode

doc/api/process.markdown

@@ -164,22 +164,34 @@ that writes to them are usually blocking.
 
 ## process.stdin
 
-A `Readable Stream` for stdin. The stdin stream is paused by default, so one
-must call `process.stdin.resume()` to read from it.
+A `Readable Stream` for stdin. 
 
 Example of opening standard input and listening for both events:
 
-    process.stdin.resume();
     process.stdin.setEncoding('utf8');
 
-    process.stdin.on('data', function(chunk) {
+    process.stdin.on('readable', function(chunk) {
+      var chunk = process.stdin.read();
+      if (chunk !== null) {
         process.stdout.write('data: ' + chunk);
+      }
     });
 
     process.stdin.on('end', function() {
       process.stdout.write('end');
     });
 
+As a Stream, `process.stdin` can also be used in "old" mode that is compatible
+with scripts written for node prior v0.10.
+For more information see
+[Stream compatibility](stream.html#stream_compatibility_with_older_node_versions).
+
+In "old" Streams mode the stdin stream is paused by default, so one
+must call `process.stdin.resume()` to read from it. Note also that calling
+`process.stdin.resume()` itself would switch stream to "old" mode.
+
+If you are starting a new project you should prefer a more recent "new" Streams
+mode over "old" one.
 
 ## process.argv