I have several cookbooks that are NOT meant to be "healthy" but use yogurt in cakes and quick breads, just because it tastes good and makes a nice texture. You can replace sour cream with it in almost any baked good and not notice the difference.
It's a little trickier in sauces and stove-top cooking. It it's not heated, it's fine, but you have to be gentle in heating it or it can "break"-- the liquid separates out and your sauce looks curdled. If you're using yogurt in cooking, add it at the very end and just cook until it's heated through. Try to avoid letting it boil.