Clay Shirky's "Law" is Valid

After reading Clay Shirky's Laws, Weblogs, and Inequality, a lot of things began the make sense. In the past, I've heard many examples of what he writes about, but it was useful to see an actual theory (with mathematics to prove it) come forth.

In class, we talked about how Capitalism tends toward monopoly, especially when it comes to new media. Think about it - any giant we know on the Internet is so successful because of its uniqueness and lack of competition. (I guess I should say legitimate competition). These successful ventures also create a niche in their market, and then own that niche.

Let me list a few examples of giants on the web. Please comment and let me know if you can think of a legitimate competitor to any of them. I'm also going to include what their known for, and the market they've taken complete control over.

YouTube (user-submitted videos)
iTunes (legal music downloading)
Google (search engine) - no, Bing doesn't compete well
Facebook (personal social media) - Twitter can't compete directly
Twitter (micro-blogging)
Microsoft Office (word processing, spreadsheets, slide show presentations, work email)

My point is that Shirky's law is completely valid in more than blogging. "Winner takes all." The power law distribution is shifted far to the left. Anything I mentioned above is the left of its respective industry's curve. Plus, if you can think of an almost-competitor (ala Bing), still it's only maybe two competitors when there are/were dozens of attempts out there.

I welcome your comments, especially if you have a good counter to the examples I listed above.