web 2.0 is, at this time, the "end game" applications that leverage the internet infrastructure to provide distributed services that are not platform dependant for the user.
Much of Web2.0 is really dependent upon the widespread availability of high speed internet access. many of the sites that make Web2.0 are high bandwidth applications and would frankly not be overly effective or usable without high bandwidth pipes.
A lot of tech companies, while not using the phrase "web2.0", are integrating this concept into their existing marketing efforts. If you have seen the Cisco "Welcome to the Human Network" commercials, you'll know what I mean: the future of the web is not one of purely commerce but a medium with which to interconnect individuals across cultures, something that has never really been done before.
see here:
http://www.cisco.com/web/thehumannetwork/index.html