The Internet has always been shaped by who was using it. But it has always been shaped to a greater degree by the proportion of subcultures that dominated it's user-base.
Ignoring it's military DARPA roots, the first major users of the Internet were universities and academics.
These were the people that built kit computers for fun.
After Email and HTML really cemented themselves as the core services The Internet provided, we saw the first wave of the "General Public" using it. These were people that generally speaking were non-technical, yet they were computer-fluent. They were probably computer users for some time, but computers were neither their hobby, nor their profession. They used the Internet for emailing each other and browsing the web. They had money. They were working for companies that were building internal networks aggressively.
The volume of these users became great enough that there was now a group of people to sell things too. Up until this point the users of the Internet had been dominated by academic interest or hobbyists. The children of this group would grow up in a house that had a computer with an Internet connection. In the beginning it was dial-up, meaning Internet usage was like "batch mode" - you connected, did your email and some browsing, and then disconnected. Towards the end of this wave most people had ADSL, turning the Internet into something that was always on. This was a precursor to the next wave. Content is still relatively rare. It is still quite difficult to run a web site. Companies scramble for domains and set up their first "presence" in the Internet.
AOL, Yahoo, GeoCities, Hotmail
1995: GeoCities picks up speed 1996: Bill Gates writes an essay "Content is King" 1996: First release of MS Exchange - large-scale adoption in companies 1996: Hotmail released 1997: IE4 released 1997: Ads on GeoCities 1998: Google search officially launches 1999: IE5 released 2000: Dot-com bubble peaks in March 2002: Dot-com bubble ends (October) 2004: Gmail released to the public as beta
This wave is approximately marked by the development of the iPhone. It's not so much that the iPhone itself triggered this wave, but more that the general conditions that existed at the time made the iPhone a valuable proposition. Within a relatively short amount of time the world went from a mode where the Internet was accessed from a desktop computer used in "batch mode", to where it was always on and always available in your pocket. 2007.