This is an area where Web ads have a huge advantage over print.  Companies publish these ads, often made by big out of touch marketing departments or outside firms, these think they are amazing, but there is no way to get feedback.  How many people saw this, how many liked it and how many were inspired to buy our product are things that print just cannot answer.  On the flip side, web advertising gives you cold hard numbers to back up your campaigns effectiveness.  We can tell how many people saw, clicked and for web stores, you can even find out how much people spent based on the banners they saw.  You can find out something doesn't work, and change it up for something that does and reevaluate.
Companies keep making shitty ads, often because they don't know they are shitty, plain and simple.  Let brands know what you like or don't like about their ads and help them put together some awesome effective marketing.