E-mail marketing is a very old channel of communication with the consumer on the Internet https://newmediaservices.com.au/fundamental-basics-of-email-marketing-2018/. It predates social networks and even more so advertising in them. Some people talk about the death of e-mail marketing, some people talk about its ineffectiveness. But think about it, if it were so ineffective and useless, would you get a bunch of different newsletters in your inbox every day?