Facebook will soon start letting third parties merge their consumer advertising data sets with Facebook's own information, according to a post from the company early Thursday. The new system will let marketers target ads on Facebook based on what a user does both on and off Facebook, a tactic that Facebook criticized only a few years ago.

As Re/code explains , marketers have long been able to target Facebook ads using outside browsing information. For instance, if a user is searching for cooking utensils on Walmart, they may then navigate to Facebook and see an ad for KitchenAid. If KitchenAid (or its representatives) wanted to target an ad based on a user's Facebook data, they could also do that—if a user's interests include "lasagna," they might get a KitchenAid ad with a beautiful lasagna next to a stack of food storage containers.

Under the old system, KitchenAid could not integrate these two sets of information. Now things are different: KitchenAid can take your Facebook love of lasagna and Internet search for kitchen utensils and show you a lovely chrome-plated spatula supporting a nice, thick slice of your favorite food.

The change comes after Facebook has spent years trying a bunch of different tacks with advertising, including mobile ads and "social ads" involving brands' posts to their own Facebook pages. To help users with its uncannily accurate new ads, Facebook is introducing a new drop-down menu that lets readers ask why they are seeing them, as well as edit an auto-generated list of preferences based on their activity (Google does something similar). If users don't like the ad in particular, they can hide it. If they do like it, they can tell Facebook it's "useful."