Yelp will be adding call tracking to its wildly popular review site so it can measure the amount of phone traffic it provides to businesses. By doing this, Yelp will be able to get an accurate view of how much business it is driving to the companies it lists.

The call tracking will be handled by call measurement solutions provider Telmetrics. Yelp already serves 45 million visitors each month and as we recently reported, it is one of the few social networks in the top 50 websites with the highest amount of unique visitors.

“We look forward to working with Telmetrics to better understand the impact and value that Yelp profile pages can deliver to businesses,” said Lemar Hight, director of Yelp’s business operations and finance.

It makes sense that Yelp wants to measure their usefulness. They are constantly refining their site to move more people into local businesses. For example, they just recently added a feature that lets you make reservations through a restaurant’s Yelp page. Since they provide company descriptions and reviews as well as addresses and phone numbers, it’s about time Yelp got credit for all of the pizzas I order because of them.