Olive oil is a low smoke point. It's good in a salad dressing but bad to cook something like steak and terrible for frying foods. It burns at a temperature lower than you'd sear meats at. Low smoke point oils tend to be richer and more delicate in flavors.

Canola is a mid-high smoke point oil, it's good for searing meats and frying foods.

Safflower and avocado are a high smoke point oil. You can cook at a much higher temperature without burning the oil.

If you can find a place to watch it, there are a couple episodes of Good Eats where Alton Brown goes over the different types of oils and their usage. I find his show to be great at learning the whys behind a lot of the cooking choices and techniques.