Is Facebook really worth $100 Billion dollars?

How much are you willing to pay for information? Advertisers are willing to pay for access to potential consumers. I don't think Facebook is worth more than Google or any other company that makes tangible products like Microsoft. I realize that internet applications and social networks are a big hit with younger kids and can be very addicting, but I think it is strange that people are investing so much time and energy into something that exists only on their computers and in their minds. I guess I'm a hypocrite because I invest my own time and energy into writing this blog how to make a million dollars, but that's alright. I can rationalize the time invested with the amount of knowledge attained and the actions I take to right my finances. Do you think web applications are more valuable than things you can touch and feel and work with?