How are personal (specifically according to your criteria) mailing lists made?

Question

PHP

Hello! Many of us have experienced such a phenomenon as mailings, when we buy something in stores or register on some major resource. Even the most dubious online store, when you buy some trinket there, after a while starts sending you lists of goods based on what you have already bought. Yes, take the same Habr or Toaster. Habr sends only articles from the hubs to which I am subscribed, Toaster - only questions on the tags to which you are subscribed. Interested in a purely practical side of the issue. For example, mailing is carried out once a week for all recipients. There are, for example, a million users, and these are only those who are subscribed to this mailing list. Most likely, some kind of script is launched that bypasses all these subscribed users in the database, looks at what criteria each has, and already for each user separately generates a letter according to the criteria for this user. You can tritely run a cron script that will send these letters with phpmailer, but it sends each letter for a couple of seconds, with so many letters it will send them forever, a week is already suitable for a new portion of mailings, but he has not sent the old ones yet))) And if you first throw everything into the database and send it slowly, all the more so he will not have time to send everything in such a way before the next mailing. I looked on the Internet, they only offer template settings for well-known mail clients for housewives, or all sorts of dubious spam messages, but I don’t need spam messages, but legal mailings like on Habré. Well, all these paid mailing services such as SmartSender also allow you to personalize the templates and send one canoe to everyone. Generally,

Answer 1

The horsemen mingled in a heap.
1. Nobody makes big mailings with a PHP mailer. For example, a script is used that generates letters and puts them in the MTA queue, and further letters are sent by the MTA (with the correct configuration, for example, Postfix, sending a million letters from one machine in a few hours is not a problem). If necessary, the script is run in multiple threads / on multiple machines. Even more often, instead of a local MTA, the email service provider's API is used (your idea about it is not correct, you just don't know how to use it), because. a million letters from you will not be accepted by any postal service until you accumulate a normal reputation.
2. Users are segmented. The more segmented, the better. First of all, in terms of activity, if a user has not visited the site for a year, and you send him something every week, your letters will almost certainly end up in spam. It is also possible to segment by gender, age, geography, income level, new user / regular user / leaving user / lost user. The frequency and types of mailings are determined by segments.
3. Newsletters are personalized based on the previous activity of the user and his segments.
4. Newsletters are split-tested. The most efficient ones are selected.
5. Newsletters are triggered. Spamming a user once a week by giving him a sheet with a list of products is ineffective. It is much more effective to hook him at a certain point in time with a specific offer. For example, if a man bought something feminine (perfume, flowers, coffee) - remind him of this exactly in a year and offer something that can go well (update, supplement, replace) with the first purchase. If he bought a gift for a newborn, offer a gift for a one-year-old child in a year. Birthdays and other significant dates like to be repeated. If he bought a bike, then a month later something for him - offer another month (by the next RFP) a discount on some other accessory specifically for this bike (if the cycling season is not over yet, of course). A good offer should come more than once a week, but then,
PS Read materials on e-mail marketing.