Etienne,
I think there are 2 problems here.
1- Clarity of the message. I agree it is sometime impossible to understand what the message is. I often find myself in front of the television laughing but not for the right reasons.
I think the Budweiser Light television ad is in part a good example. When Mr. Budd Light says to a bunch of German with sausages “there won’t be any sausages party tonight my friends”, I simply don’t get it. What’s the point of wasting 10 seconds on something people don’t understand? First degree humour… I get it, but it doesn’t reinforce the brand at all.
2- Clarity of the brand announcing. You will have to do a post on this. How many times have you been in front of an ad not even knowing who was the announcer? You’ll remember the ad, but you simply can’t pin point the brand behind it.
At the end of the day, I think a great ad is one that makes it easy for people to remember (with the right message in line with your brand positioning), but above all, it’s an ad that will be clear enough to understand the message and also to identify the brand behind it.
Have a great weekend.
Alexandre