Have you ever given much thought to the glossy catalogs that routinely show up in your mailbox, offering you great deals on the exact things you need? Or maybe how your favorite online stores know to send you offers for summer dresses rather than men’s dress shirts? When you’re getting what you want, wondering about how it got there is an afterthought. But, you might be surprised to know that your shopping experience—both online and off—is the result of contact strategies at their best. Let’s take a look at exactly how these contact strategies work.

It all begins with the customer. Say that an advertiser would like to targetfemales who are interested in makeup. It might seem like a simple enough matter, but this is where all the variables come in. How old is the customer? What kind of makeup is the customer interested in? How often does the customer buy makeup? A high school student partial to glitter eye shadow is vastly different from the vice president of a large company with a need for neutral shades. The two will differ not only in the type of makeup they buy, but also in how much they spend and how often they buy. Companies want the customer to purchase as much as possible, so customer characteristics are important. This is where customer segmentation begins. The breakdown begins in terms of messages, offers, and the frequency of contact with the customer.

Companies with strong contact strategies target different groups of customers with unique messages. Let’s say that you love makeup, you wear it every day, and can’t get enough of it. You have a favorite makeup company that you buy from all the time. That company is likely to treat you differently from the other groups customers might fall into. There are new-comers who have not bought from the company before, customers who only buy occasionally or sporadically, loyal customers who buy consistently (the group you fall into), and maybe even those who used to buy on a regular basis but don’t anymore. These groups vary from company to company and might be broken down into even more sub-groups.

While loyal customers will likely buy from the company regardless, newcomers need to be enticed with special offers. I’m sure that you must have been offered free shipping or a 10% discount on your first purchase at one place or another. Special deals are also used for the purpose of winning back old customers. But, it doesn’t end there. There is no lack of holidays—from those as traditional as Christmas all the way down to National Donut Day—that retailers use for the purpose of making a sale.

Flash sales, seasonal promotions, and events that occur monthly or weekly all engage customers to make purchases. Why not buy something if it’s ‘Buy One Get One Free’ Tuesday? And how can you refuse to buy from a catalog full of images of buttery croissants and irresistible chocolates? And you must try the new product; it’s on sale! As companies learn customers’ buying patterns and interests, they are able to cater better to those interests, and in turn develop better contact strategies.

It’s not only about getting different messages out to different sets of customers. Companies are pushing even further to keep the customer engaged. I recently did some online shopping myself—appropriately enough for makeup at Sephora—when I got an email reminding me to complete my order. Somehow life got in the way of hitting the ‘submit’ button, but Sephora was kind enough to remind me to finish my purchase. Contact strategies are key in situations like this. Sephora had to be sure that I was the right customer to be reminded about my purchase. Someone else might have considered this reminder pushy or unnecessary.