If you put up photos on your ad and just make sure it's well-written and clear, it's great for looking for roommates. Get some good photos, especially one of the room(s) you'll be renting. Make sure you include the price.
Don't include your phone number in the ad, have people reply to the ad and then send it back to them. I've heard of people being scammed over the phone when they include their phone number.
I've used craigslist to look for a few places in Minneapolis, it's a great tool for finding places to live.