Gmail has added another feature in labs- Canned responses. With Canned Messages you will be able to save a reply you’re writing as a “canned response” and then quickly select one of these responses when you’re replying to a future e-mail. With Gmail filters you can sent this canned message as auto reply to specific mails. To activate this feature, go to Gmail labs and turn on Canned Responses.
Whenever you compose a mail, you can save the message as canned message by using the link below the subject line.
Using filters in Gmail, this canned message can be sent as auto replies to mails from any ID or using any particular format. To set up auto reply, create a new filter and in the settings you can select this canned message against the option “Send Canned Response”.
With this feature, you can sent vacation responses and also different automated messages for different keywords in the filter. This is pretty useful feature from Gmail Labs.