We all know that Facebook is everywhere. And most of us know that the company has been challenged on its privacy policies and it use of personal information. But sometimes I have a slightly broader concern with the popularity of the social networking giant: I think it may be dumbing down the web–and the web user.

Here is what I mean: we are entering the downhill slope of the 2.0 revolution–the changes in the structure and functionality of the web exemplified by YouTube, Wikipedia, and yes, Facebook. The 2.0 idea–namely, that users create and organize content through huge, interwoven social networks–is being seriously challenged by the unchecked growth of Facebook. Facebook wants to be the web, in the same way that Google is virtually synonymous with being online. Facebook, in other words, wants people to say, “Where’s that restaurant again? I’ll Facebook it. ” Or perhaps more ridiculously, “I’m Facebooking my article right now.” (see my recent post on the new Microsoft/Facebook partnership).

The trouble with this is that Facebook is crowding out other innovative 2.0 companies as it gobbles up more and more user experiences. Why keep a blog any more? All of your friends and family members (in other words, the people who actually read your blog) are on Facebook already. Just post a note there. Why upload your photos to Flickr, the photo sharing site whose features far exceed those offered by Facebook, when your photos have a much better chance of being seen at Facebook?

Part of the idea of web 2.0 was that users can create a highly customizable web experience with absolutely no coding experience. This experience went something like this: go to WordPress, start a blog, add a blogroll, embed your video from YouTube, publish your podcast, syndicate your feed, and alert your friends and family. Now, the idea of web 2.0 is this: Facebook.

The dominance of Facebook–and the limited user experience that results–is somewhat akin to the Apple experience. A life-long Windows user, I’ve switched to a Macbook Pro. I really like the computer, don’t get me wrong. In fact, I still can’t figure out why the Windows clones cannot be a sleek or as well-designed as the Mac. But I have noticed that the online conversations about Macs are less about innovation (how to hack the code to make it do what you want) and more about advocacy (“Who needs to be able to cut a file? Not Mac users! Everything is better in a Mac!”) . Windows, for all of its failures, has given rise to really smart, really useful software and modifications. Windows Media Player not working for you? Try one of the dozens of free alternatives available on the web. Don’t like the version of iMovie that came bundled with your Macbook Pro? Good luck.

So, it may be that Facebook needs the equivalent of the blue screen of death. Enough users have to get fed up with its privacy violations and its interface to begin hacking its code and offering better alternatives. I personally would like to see four or five major social networks, all contending for customers. Maybe we start by quitting Facebook in favor of new startups like Diaspora. Who’s with me?