Since installing Buddypress 1.6.1, JetPack will no longer connect to WordPress.com unless you disable Buddypress first. Error message:
Error Details: The Jetpack server could not communicate with your site's XML-RPC URL. Please check to make sure http://myITforum.com/myitforumwp/xmlrpc.php is working properly. It should show 'XML‑RPC server accepts POST requests only.' on a line by itself when viewed in a browser and should not have any blank links or extra output anywhere.
Also...related, with Buddypress 1.6.1 installed, Windows Live Writer does not have the ability to connect and post using the xmlrpc.