I'm confused about recent articles regarding credit/debit card fees [View all]

I'm turning to the DU community because we have so many educated people in various fields as members. I think I read on DU that there is a new federal law that prohibits businesses from charging a 3% fee when a customer uses a debit card rather than a credit card. I've run into several merchants/businesses who had no idea this was now the law. I tried researching it myself and got confusing answers.

So, am I misremembering (wasn't that a Dubya word?) what I read here?