IBM, Microsoft, and Google -- None of them have been overthrown.

The Roman and British empires lasted hundreds of years.

Facebook will be around long after you and I are dead.

It's not another myspace or friendster. It's a firmly ingrained institution that people probably value more than their wallet at any given time.

"Overthrown" does not mean "disappear", it means "no longer king."

IBM was once the king of computing. It was overthrown by Microsoft. Microsoft was then king, but it is no longer, though those living in the past will point to its continue dominance of the PC, a dominance that is both declining and becoming more irrelevant. Google was crowned the king of the web, with users spending most of their time on google.com, but now they spend far more time on Facebook.

> The Roman and British empires lasted hundreds of years.

We're talking technology, not geopolitical power. The former operates on a vastly accelerated time scale, aka "Internet time". I recommend you read the Innovator's Dilemma, or at least the cliff notes on Wikipedia: http://en.wikipedia.org/wiki/Disruptive_innovation. There's a nice list of things many of which weren't expected to be overthrown so quickly.

I'm wondering if you might actually be a celeb: http://www.youtube.com/watch?v=eywi0h_Y5_U.

Overthrown implies a zero sum of land, etc. How relevant is IBM to modern computing? Sure, they're doing some great work in supercomputing, but there's no monopoly they control like they once did. MSFT has a solid monopoly, but their relevance is lessening though still influential in some circles. Google is young/ambitious enough that it has its skunkworks projects - gGlasses is an extension from search, and self-driving cars is from maps/geo data, but it's still not really entirely defensible from their central data monopoly.

You can say that a website that most people on it use for less than five years will outlive us ?

I don't think FB is going out of business anytime soon, but as time passes, I think that it's core value is more like its original vision -- i.e., a social directory. Seems like it'll become a repository of all your social contacts and your virtual passport when signing up for other sites and will cease to be the place where you spend all your time communicating with friends and discovering new things.

Sounds like you're suggesting Facebook may eventually become the next YellowPages. I could see that happening. It's mostly what I use it for anyway—remaining available to people who, since joining Facebook, seem to have forgotten I'm still reachable via phone, email, and IM.