Custom content like hand-written HTML via GitHub Pages for the http://osgeo.nl website.
The domain http://io.osgeo.nl directs via DNS CNAME to http://osgeonl.github.io. Hence the CNAME file here such that GH is aware. Thus never remove the CNAME file here!
Examples: http://io.osgeo.nl/sitecontent/osgeonl_dag/osgeonl_dag_2012.html http://io.osgeo.nl/sitecontent/osgeonl_dag/osgeonl_dag_2013.html