First came portals.
Then came search.
And now, with vengeance, come the more open platforms.
As Yahoo/AOL defined the first era, and as Google defined the second, platforms (such as Facebook) will define the third.
These platform companies are achieving ubiquitous user reach and they are spawning their own ecosystems. They harness the power of social grids and distributed applications. And it's only beginning. These platform companies will command monster market capitalizations, because they will be great businesses, achieving truly global scale very quickly.
As these platforms interconnect (for example: social platforms meet local meet mobile meet vertical), the consumer utility and value of applications will soar.
Who will the winning platform companies be? Facebook for sure. Google, Apple, and Amazon will likely remain huge, driven by their platforms. But there will almost assuredly be newcomers and surprises. There are always surprises.