Authorize.net asks for it, but I'm pretty sure it is not even used.
Code:
$transaction = new AuthorizeNetAIM('YOUR_API_LOGIN_ID', 'YOUR_TRANSACTION_KEY');
$transaction->amount = '9.99';
$transaction->card_num = '4007000000027';
$transaction->exp_date = '10/16';
It looks like the above is all that is required to send to them. Though I thought address verification was part of the process?