diff --git a/haml.gemspec b/haml.gemspec
index 29757ba3..3a70204f 100644
--- a/haml.gemspec
+++ b/haml.gemspec
@@ -1,6 +1,10 @@
 require 'rubygems'
 require 'rake'
 
+# Note that Haml's gem-compilation process requires access to the filesystem.
+# This means that it cannot be automatically run by e.g. GitHub's gem system.
+# However, a build server automatically packages the master branch
+# every time it's pushed to; this is made available as the haml-edge gem.
 HAML_GEMSPEC = Gem::Specification.new do |spec|
   spec.rubyforge_project = 'haml'
   spec.name = File.exist?('EDGE_GEM_VERSION') ? 'haml-edge' : 'haml'