Facebook is poised to dominate the next iteration of the web (commonly referred to as web 3.0 or the semantic web) in the same way, and for the same reasons that Google dominated web 2.0.
How did we get here?
Web 1.0 was dominated by portals and rudimentary search engines. We intrepid netizens found things on the web as they were actually cataloged by humans. Think about the Open Directory Project as an example, or the basic Yahoo directory. We “drilled in” manually in order to find things. This method of finding content lived alongside the very rudimentary search engines of the day, primarily because the quality of recommendations from those engines was pretty poor and easily manipulated.
Google’s arrival on the scene marked (for me at least) a dramatic shift in what mattered on the web. By relying so heavily on citations and links, Google was able to recommend content that was trusted or viewed as authoritative by others on the web, increasing reliability of search results. Obviously, this makes it easier to find what we are looking for (to a point) when compared to what came before.