I'm a little confused as to what constitutes a high value customer". Wouldn't a customer, to qualify for the title, actually have to buy something?
This is more like "high value mall-rat" than customer.
Here's (roughly) how it works: advertisers bid in real time for ad space on sites. They use what they know about you to determine how much they want to bid for the ad you're about to see. If they want to advertise for some car dealership, people who have searched for cars are more likely to click on an ad for a car dealership, so the advertiser who wants to serve a car dealership ad will make a higher bid than the advertiser who is hocking gummi bears.
If you know enough about which user characteristics indicate that someone is more likely to spend money somewhere, then you can make a bot that has a profile similar to that type of user. If you in turn own the site which is hosting the ad space, page views on your site have an increased value, which translates to more revenue for you.