I heard this word today and I think it's brilliant:
To describe - heck, let's borrow freely from Wikipedia here - It is often used to denote persons who voluntarily acquiesce to a perceived authority or suggestion without sufficient research to understand fully the ramifications involved in that decision, and thus undermine their own human individuality or in other cases give up certain rights. The implication of sheeple is that as a collective, people believe or do whatever they are told, especially if told so by a perceived authority figure believed to be trustworthy, without critically thinking about it or doing adequate research to be sure that it is an accurate representation of the real world around them. The term is generally used in a political and sometimes in a spiritual sense.
XKCD have a great Sheeple cartoon, very thought-provoking:
Someone's also made up a mock 'Sheeple' magazine:
Question is, is the Sheeple concept demeaning to sheep?