There are such treasures that hide rather than show. Well, if only so that our treasure does not change its owner. For example, some collectors of art, this one by the great “SZ”, hide their most beloved and pampered acquisitions in places accessible only to them. And what is the most valuable treasure for brands today? Information. The one about the client. Each one individually. Our treasure is therefore called big data - now a legendary phrase that everyone has heard about, but looks different with everyone, or does not look at all. Big data is such a cylinder of an illusionist - it is as if everyone knows that something is there, but only a few manage to get a really good, white rabbit out of it. Only that the date is not always big enough to meet our expectations, or more often it is even too big, so by dipping your hand up to the elbow in the cylinder and looking for our rodent, like a phone in a woman's purse, we can come across a lot of other things that can not be arranged. Therefore, a well-organized and used customer database is a treasure. And how to take care of this treasure so that it does not slip away?