With Mailster you can send birthday greetings to your subscribers. All you need is the birthday as a custom field.
To setup your custom autoresponder can take some time and event then you may have troubles get things going.Please check following points if you troubles with your autoresponders:
Mailster can use RSS Feeds to automatically create your recurring autoresponders. This method is useful if you like to use content from a different website. If you like to use posts from your own site (where Mailster is installed) you better go with regular dynamic tags.