Delaware adopted the yield at stop signs a few years ago.
Some above are missing the point of the law. Going through stop signs is permissible when safe to do so, meaning no cars near. When a car and bike approach, it's not safe and the bike should honor the sign and stop. If the car waves you on, fine, but physics demands that the car has the right of way. The bike is +/-20 pounds and the car is +/-3000 pounds. It's like bringing a knife to a gun fight (actually a butter knife). In short, when bikes and cars are sharing the road in near proximity, bikes should follow the same rules as cars. The new laws apply when there are no cars near. It's also common sense.
Someone above asked why the law took so long. My observation is that many/most legislators haven't ridden a bike since they got their driver's license