Before the early 2000s, internet advertising was chaotic and spammy, until the governments began regulating it with laws, like the CAN-SPAM Act of 2003. Since then, marketers must get user permission to advertize via channels like email, SMS, messengers, or push notifications. Moreover, massive competition for user attention made businesses switch to a customer-centric approach. As a result, internet advertising is more personalized and relevant than ever before.