Yes, I know that money is a good thing, but when a company starts to go overboard on advertising and monetization, they start to lose users. I'm afraid that is what is going to stat happening with the hip app DrawSomething. The number of users playing the game daily is already dropping, and has dropped so much that it is back to the level it was at when Zynga acquired the app.
Zynga is adding advertising to DrawSomething, in addition to the current banner ads and paid versions. This time, Zynga wants DrawSomething users to draw brands or words associated with brands or picked by brands. The National Hockey League has already paid Zynga for this, hence why you may have been asked to draw 'puck,' 'Zamboni,' or 'slap shot.'
OMGPOP had actually been testing this before the acquisition by Zynga, so this move isn't exactly surprising. It's pretty clear that brands would pay for this sort of advertising, but let me suggest a feature. Zynga, if I am drawing brands, you should save all the pictures for that brand and give them to them so that they could be used in marketing.