The 1990s were the decade in which (particularly late in the decade) cell phones and the internet really started to take off. These sorts of technologies started to change people's lives in ways that are familiar to us today.
All of these new technologies started to make information more easily available. Instead of having to rely on printed books, it was now possible to use websites to find information, though Wikipedia was not yet in existence and Google was not anything like it is now. Continuing advances in computer technology affected people in many ways. They allowed people to play more realistic games on computers. They allowed people to do more in the way of creating and printing documents. These sorts of changes increased the number of entertainment options and made many tasks (particularly for students) much easier than they had been only a decade earlier.
This is a great question. It is important to start with a few technological developments that started in the 90s. The Human Genome project started in 1990. The Hubble Space Telescope was also launched in the same year. GPS also became operational in the 90s. On the computer front, HTML and the Web came into its own, which means things like email became more popular.
Just a cursory glance at this list will show how much technology has impacted our lives.
On the medical front, there have been amazing breakthroughs, which promise even more. For example, the Human Genome project holds the promise of increasing the quality of life by mapping out diseases and other ailments.
On a social front, think how much email has impact the lives of all people. It is arguably the most used format for communication. When we add the world wide web, the impact is nothing short of stunning. The Web in many ways has democratized knowledge. The average American is better off now than before on account of these developments.