If you are using YourMailingListProvider for news letters, then you can use the API features to convert your visitors who comment on your blog to your newsletter subscriber.
function kish_ymlp_add_commenters($comment_ID){global $blog_id;require_once 'YMLP_API.class.php';// variables: your key & username$ApiKey = "yourapikey";$ApiUsername = "yourYMLPusername";$GroupID="GroupId of your newsletter list";// create API class$api = new YMLP_API($ApiKey,$ApiUsername);$com = get_comment($comment_ID);$name = $com->comment_author;$Email= $com->comment_author_email;$OtherFields["Field1"]=$name;if($GroupID=="" || $com->comment_approved=='spam') {return false;}else {$OverruleUnsubscribedBounced = "0";$output=$api->ContactsAdd($Email,$OtherFields,$GroupID,$OverruleUnsubscribedBounced);}}add_action('comment_post', 'kish_ymlp_add_commenters');
Your can download the YMLP_API.class.php file from your YMLP dashboard under the API menuI feel its not fair to just automatically subscribe your blog responders without their knowledge. You can have a check box under the comment submit form and let them check if they want to sign-up for your news letter.
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