diff --git a/py/net/greenexecnet.py b/py/net/greenexecnet.py
index 29686a0d0..765e12a4a 100644
--- a/py/net/greenexecnet.py
+++ b/py/net/greenexecnet.py
@@ -1,3 +1,17 @@
+
+""" This is an implementation of an execnet protocol on top
+of a transport layer provided by the greensock2 interface.
+
+It has the same semantics, but does not use threads at all
+(which makes it suitable for specific enviroments, like pypy-c).
+
+There are some features lacking, most notable:
+- callback support for channels
+- socket gateway
+- bootstrapping (there is assumption of pylib being available
+  on remote side, which is not always true)
+"""
+
 import sys, os, py, inspect
 from py.__.net import greensock2
 from py.__.net.msgstruct import message, decodemessage
diff --git a/py/net/greensock2.py b/py/net/greensock2.py
index a4e28e233..0525f4694 100644
--- a/py/net/greensock2.py
+++ b/py/net/greensock2.py
@@ -1,3 +1,10 @@
+
+""" This is a base implementation of thread-like network programming
+on top of greenlets. From API available here it's quite unlikely
+that you would like to use anything except wait(). Higher level interface
+is available in pipe directory
+"""
+
 import os, sys
 try:
     from stackless import greenlet
diff --git a/py/net/pipe/__init__.py b/py/net/pipe/__init__.py
index e69de29bb..ac07348e1 100644
--- a/py/net/pipe/__init__.py
+++ b/py/net/pipe/__init__.py
@@ -0,0 +1,8 @@
+
+""" This is a higher level network interface based on top
+of greensock2. Objects here are ready to use, specific examples
+are listed in tests (test_pipelayer and test_greensock2).
+
+The limitation is that you're not supposed to use threads + blocking
+I/O at all.
+"""