It seems to me that Michael Jackson's/USA for Africa 1985 video
"We Are The World" may have been a important precusor
to will. i. am's 2008 "Yes I Am" music/political video.

"We Are The World" focused on the social cause of helping to end hunger in Africa. "Yes I Am" focuses on the 2008 USA Presidental campaign. However, both projects successfully use music and visuals for more than just entertainment purposes.

Here's a link to a YouTube video of "We Are The World":
http://www.youtube.com/watch?v=ne7fPpxAnuM

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One of the main similarities between "We Are The World" and will. i. am's "Yes We Can" video is how both videos feature of a number of different celebrities.

Click on http://en.wikipedia.org/wiki/USA_for_Africa to see a list of the celebrities who are featured in "We Are The World".

Click on http://en.wikipedia.org/wiki/Yes_We_Can for a list of the celebrities who are featured in the "Yes We Can" video.

There's no question that both the "We Are The World" and "Yes I Can" videos were ground breaking. It'll be interesting to see what innovations will come next in the music/videos meet politics and/or social causes realm.