Yes, the web matters - duh. But, its major impact is yet to come. Currently it has democratized (somewhat) information, changed the way we share, communicate and learn - along with about a million other things. However, the large scale social, psychological and economic ramifications have not happened...yet.
Let's leave out the psychological discussion for now (does having 500 "friends" on Facebook increase closeness, dilute actual bonding with family? what happens to a generation that grows up sharing video, photos, private moments with Dear@www - how does a 1:1 relationship, be it marriage or parenting stack up to or compare? and so many others).
What is really interesting right now is the tapping of the collective wisdom of crowds, social networks, starfish theory, desire for fame, money, social capital - whatever you call it to find serious solutions to major global problems.
The big case in point here is Google with their Project 10^100. According to Google "Project 10100 is a call for ideas to change the world by helping as many people as possible." Seems like a perfect use of some of their money, brand equity and the web.
I, for one, am very excited to see what comes out of the project. My guess, some amazing mind blowing ideas, game changers and a few "smack me sideways - why didn't I think of that" ideas.
Google video is below - and go post your ideas!