The options may include: confirming the link, confirming email; password to confirm your subscription. Unconfirmed subscription is invalid, and for a mailing address is not made! Note that a confirmation should not have any sense of advertising and should in no way affect the choice of the subscriber. The letter should be only: the name of the mailing of its author, subscriber data, date subscriptions, technical source distribution can be instructions on how to confirm your subscription, how to stop it and how to manage it. "SPAM" – a mass mailing e-mails with information of advertising or otherwise to email-address, the owners of which did not give their consent to receive such information. Your future self subscriber must agree to your feed and subscribe to it only voluntarily. MongoDB: the source for more info. If he liked you personally, if he like a description of your mailing list, or if he is interested in your topic designations. Therefore, the "mailing list" could be called just a mass mailing emails, in which there is: a list of email-addresses, sformirovnny by voluntary subscriptions; mandatory confirmation of subscriptions for the subscriber on the mailing list; issues at specified intervals, completely relevant to the content, which was originally interested subscribers distribution; detailed instructions in every issue of mailing to manage its receipt (unsubscribing, delete) and manage subscriber data; If a delivery does not meet these conditions, it can not be called "Mailing" and can not be effective. In any case, such a mailing will be problems (sometimes very serious), and its profitability will be very low if any, will be.