I have a .eu e-mail address. During the first few weeks of the .eu regime Amazon did not recognise my new address although they very quickly put things right. Since it took rather a lomg time to go through the numerous sites that require addresses I did not want to go to yet another address for the sites which did not recognise .eu (only Amazon as it turned out)
I have now discovered that BT do not appear to have kept up with the arrival of .eu. I have 2 contacts who have btinternet.com addresses and they do not receive e-mails from my .eu account but do receive from my co.uk account.
I suppose its either very patriotic or downright lax!!