In excluding members of the Episcopal Church from Anglican bodies engaged in ecumenical dialog Rowan Williams was no doubt trying to send a message to... well, someone or other.
Among the intended audiences, I suspect, were our ecumenical partners, the Lutherans, the Methodists and others. But the message received--that Williams is willing to disrupt long-established relationships and set back the work of those bodies to pander to the anti-gay faction in the Anglican Communion--is probably not the one intended.
The incredible shrinking Archbishop of Canterbury. He just keeps getting smaller and smaller.