Here's a brand-new buzzword that is getting some legs: crowdsourcing.
It's a general term for the idea of "outsourcing" an activity to "the crowd" - in other words, the public. It's not strictly a marketing concept: things that depend on users to generate content, or code, or any usable product are examples of crowdsourcing. Linux and Wikipedia are probably the best known examples, and word of mouth could be called "crowdsourcing" in a general way.
In marketing circles, the most buzzworthy example of crowdsourcing is consumer-generated media.
The appeal is obvious: why pay an agency to develop creative when you have customers or users who want to do it on their own?
Well, as with any neat idea, there are some things to be cautious about.
You can learn a lot from an exercise in crowdsourcing. If you ask your customers to create some ads or slogans for you, you're going to find out how they think of you - and how that differs from what you thought was your brand position.
Of course, you might find out that some people really hate you, as happened to GM when they asked people to create ads for the Chevy Tahoe. The site was mobbed by people who hate SUVs. The results were nothing to make a brand manager happy.
It's important to keep all of that in perspective. Crowdsourcing of all varieties by its nature attracts the most passionate users in the crowd - and they may be people who aren't your customers and never were going to be your customers.
The worst thing you can do is react to something like that without first asking, "Do these people really matter to us?" People who hate SUVs aren't going to buy one no matter how you market it. For GM to give them a platform to express that isn't a great marketing move, but trying to react to that only would compound the mistake.
And thus I get to my problem with the word "crowdsourcing." It's not outsourcing. When you outsource an activity or process, you can expect a reliable final result. Outsource creative work to an agency, and you should expect creative that meets your requirements. Outsource it to the crowd, and you will get what they want.
That's probably going to be educational, and might be usable, but it's not really outsourcing; it's part of the marketing conversation. You should experiment with consumer-generated media, you should look for ways to use it to get your best customers more engaged with your brand... but you shouldn't mistake it for a way to offload an expense. If you do that, you're likely to find that you don't own your own brand anymore.