The leaf itself doesn't taste like much other than, well, a leaf. But steep a few leaves in a warm broth or sauce, and your dish becomes infused with flavor and very fragrant. It's not usually a very forward seasoning, but its woodsy flavor and slight bitterness helps to balance the flavors in a dish. You'd miss it if it weren't there.
If you're not sure you know what bay really tastes or smells like, a good experiment to try sometime is to put a few bay leaves in a cup of boiling water. Let it steep for a few minutes and then take a big whiff. On its own like this, it's hard to believe anyone ever thought to put bay leaves in their cooking!
Bay is typically used to season long-cooking dishes like soups and braises, but it can also enhance the flavor of quicker-cooking dishes like risotto, pasta sauce, or even a simple pot of rice. The key is to have at least a little liquid for the bay to infuse and heat to get the process going.
The herb is used most widely in Mediterranean cooking, but since it was one of the earliest and most widely traded spices, bay has become an established seasoning in many cuisines around the world - most noticeably Indian, the Middle Eastern, and many European cuisines. It's also one of the main ingredients in a classic French bouquet garni.
Do you use a lot of bay in your cooking?