They're down right now due to the spike in traffic.
Meh, I don't see this as the downfall of Google. The problem is that Google has such a massive share of the search engine market that it's usually the first search engine most users point at for a search. Granted, their Adwords technology has run its course in what's relevant, it still garners a massive audience as for the most part, their search is usually spot-on. Furthermore, Google is built around a series of products that are one way or another, linked up to their core business (i.e. Gmail, Desktop). It doesn't matter how innovative Cuil is, it's just grasping at straws to fill a significant market niche. My take is the article you read is more PR hype.
The closest thing that can tackle Google is Facebook because their application platform could have the potential of circumventing text search with more meaningful results thanks to the social networking element. However, it still has some ways and kinks to work out before it becomes that disruptive enough to topple Google. The future isn't in social bookmarking search engines, indexed primarily by humans not software, like Mahalo but they do have the potential for getting a good cut of the market given that their offering is a bit unique.