In accordance with an article on the Dairy Industry Association of Australia's webpage, yoghurt has 30 days from the date of manufacturing. Your yoghurt is best eaten within the first two weeks as this is when has the highest bacteria count. After 2 weeks the live bacteria start to decline so by 30 days you only have 15% live bacteria left. This would be a great time to use your yoghurt in any of your cooking.
Your yoghurt also gets tangier as the weeks progress with the bacteria still being active and creating lactic acid.