The Internet -- as the TCP/IP backbone network -- has been around for a long time but the World Wide Web ( or simply the "Web" as we know it) really took off with Netscape.
With its genesis in Mosaic / SpyGlass ... Netscape was the first icon of the fledgling Web and the Netscape IPO is very often taken as the first milepost in the long journey. That was the First Era, the era of Netscape.
But Netscape was shouldered aside by the marketing might of Microsoft but strangely enough was not quite replaced by it. Despite trying so hard and with its flagship IE becoming the default browser by sheer brute force, it was not Microsoft but Yahoo that symbolised the Second Era. With Tripod, Geocities and other web properties under its belt, Yahoo was the big boy and the definitive icon.
But like hot adolescents that grow into pot bellied middleage, Yahoo too had to give way to next emerging hotshot .. that is Google. The Third Era of the Web was symbolised by Google .. the icon of innovation that took something as humble as search ( for which Yahoo was so well known ) and monetised it into a multibillion dollar advertisement distributor.
Google can apparently do no wrong ... whether it is buying Orkut or YouTube or flaunting its principle of doing no evil ( and thus indirectly stating that Microsoft is the evil empire ) it took the web where no one has taken it before ... at least in hype and hope !!
But then again, nothing is permanent and neither can be Google !!
So is Google's days numbered ? Not likely .. even COBOL exists today .. but the baton is being passed to new generation of Web 2.0 players ... and who symbolises Web 2.0 ? The jury is not yet out ... but if I were to lay my bets, it would be on Facebook.
This is the Fourth Era - the era of Facebook, the era of Web 2.0. What is web 2.0 ? It is all about (a) user generated content and (b) rich media and while many players are trying very hard to crack this .. I believe it is Facebook that will finally triumph ... until someone else arrives.
Netscape >>> Yahoo >>> Google >>> Facebook .... each an icon of its own era on the web.