Over the past five years, Yelp added health inspection scores to over 200,000 business pages. It now expects that number to balloon to nearly a million as it incorporates ratings from the official Health Department Inspection Scores database, which covers 42 states and a third of the population in the country. The website has already added data for more restos in New York, California, Texas, Illinois and DC and plans to continue adding more, state by state, in the coming months.

In its announcement, Yelp referenced a study that looked into the impact of publicly posted hygiene grade cards on restaurants in LA County. The study found that the more visible the ratings are, the lower the number of hospitalizations due to foodborne illness is. After all, businesses will likely strive to improve their hygiene practices if they know that customers can see if they're lacking in the cleanliness department.