"meme (pronounced /mi¢°m/)[1] comprises any idea or behavior that can pass from one person to another by learning or imitation. Examples include thoughts, ideas, theories, gestures, practices, fashions, habits, songs, and dances. Memes propagate themselves and can move through the cultural sociosphere in a manner similar to the contagious behavior of a virus."
-http://www.answers.com/topic/meme

This thread is not just about Juan Williams.

I started this thread out of concern that left alone, Williams and other of his ilk would succeed in establishing the meme that "Michelle obama was an angry Black woman who hates America".

Although I agree that "Memes propagate themselves and can move through the cultural sociosphere in a manner similar to the contagious behavior of a virus", I also believe that most memes don't get embedded in people's minds overnight. Those who seek to implant these memes prefer the slow and steady drip drip drip of poison until the meme they have started becomes so deeply rooted that it would be very difficult to extricate.

Unfortunately, America's history of racism & sexism and the fact that racism and sexism have not been eradicated just because we have a Black President, mean that there is still fertile soil to plant this particular pernicious meme about Michelle Obama.

For example, see this YouTube video:

Racism in Disney Movies