In advertising, a hybrid (also called a PBTI, or 'Pod-Based Tie-In', which is unweildy as all hell as a name) is a particular kind of television spot - the most common kinds are designed to appeal to the show currently being aired and to offer incentives to the viewer. For instance:

You're watching What Not to Wear. During a commercial break, one of the stars from the show appears and offers fashion advice to a confused-looking woman in a baseball cap. Stacy, the star, advises her quarry to try this new conditioner from, say,Herbal Essences, to eliminate friz or something. After Stacy is enthusiastically thanked by her victim, an announcer states that even more style tips can be found at the What Not to Wear website, and offers a URL to the same.

Tacky, right? But it works, and works well. Herbal Essences might not get the return that they want, but TLC gets website stats from every visitor and can (crudely) measure engagement by measuring the peak in site traffic when the hybrid airs. And, having been sponsored (and paid for, natch) by Herbal Essences, TLC might even make money in the deal (though usually not), so it's all good.

These particular ads are called 'hybrids' because, starring recognizable facets of the show as they do, they essentially advertise two different products (a consumable and a program) in the same commercial, blurring the traditional line between content and advertising. They also (usually) contain something called a 'call to action' - an appeal to the viewers to actually do something, in this case to log onto a web site.