Stephan Okhuijsen (a project manager on one of my former projects) published before on the subject.
Some interesting, but not stake holding, arguments and conclusions were:
- The snarky and malicious interpretation is that most people who read blogs are idiots, but there are slightly more (roughly 10%) right-wing idiots than left-wing idiots.
- Many readers will be surfing from work, where they're forced to use IE.
- Oh, and yes, lefties are smarter, sexier, funnier, more sophisticated, better groomed, more articulate, kinder, more thoughtful, more moral, have better pets, and are way cooler than righties.