Because you won't talk to your customers in the same way, depending on their consumption habits... This is called segmentation, and it's what we do at Hey Pongo.
Enrich your CRM, and make the right choices, by asking them regular questions.
Ask your customers for their opinions, get them involved and co-create with them. The only limit is your imagination: ask them for their opinion on a new product launch, what their favorite soccer team is, how they heard about you, whether they'd like to take part in your events, identify your influencial customers, etc.
By running your own surveys, you can gather even more data about your visitors. Based on your customers' responses, you can adapt your messages to make them even more relevant to them.