In the ’90s, you had a large machine and several thin clients accessing it by using X11 via network. In 2010, you will have large datacenters providing applications to and storing the data of millions of users. As you might have guessed, I am talking about Google Chrome OS.
It seems that the PC era is slowly coming to an end, with devices being increasingly connected ‘to the cloud’ and people being always online; and storing their data on Google’s servers. We do emails online using Google Mail, we do navigation online using Google Maps, we edit and view our documents using Google Docs, our newspaper is Google News; and when we want entertainment we open the browser and type youtube.com into the URL bar. Even if we were formatting the hard disk and reinstalling the system, most people wouldn’t even notice; because all there data is stored online.
There is also the question of freedom. Free software is not very widespread in the SaaS world. You also lose the control over your data. But RMS can tell you more about it.
So it seems that 2010, Google is the new mainframe and netbooks and smartphones are the new terminals. Whether this is good or not cannot be said. The question you have to ask yourself is whether you can trust Google to keep your data secure or not. I trust them enough to host all of my emails, the RSS feeds I read, my searches.