A data clean room is a secure environment that enables the connection of distributed data across multiple platforms and parties.

The first to embrace data clean rooms were "Walled Gardens." One example is when Google launched its data clean room called Ads Data Hub (ADH) in 2017. It was a cloud-based solution for YouTube advertisers to gain measurement and insight.

In response to the evolving privacy regulations, ADH has since evolved to become a replacement for the DoubleClick Data Transfer file and offers a much richer set of data for brands to access than what's offered outside of their clean room environment.

Facebook and Amazon also have developed their own data clean room environments: Facebook's Advanced Analytics and Amazon's Marketing Cloud.

Data clean rooms are not limited to Walled Gardens. Brands can develop data clean rooms of their own, and can leverage software like Habu's to more quickly accomplish this.