"The 90s" is too large a time for a single answer for this. I'd divide it into 3 different answers:
1990-1993 - This is the Pre-World Wide Web. Yes, the internet before web browsers! Internet access was the easiest and most accessible for university students and those in academia. You would have a "shell account" which would get you email, FTP, Telnet (which could offer real-time chat), and Gopher (which was the Betamax of the Web). Those not at university could access parts of this through paid online services such as CompuServe, Prodigy, or America Online (AOL). BBSes of the day also had access to a type of Internet email called Fidonet, which allowed BBS users to send and receive email (with huge batch delays) to internet users.
1993-1995 - The web is born! The web was now a thing, however it was being bolted on to the existing technology of the day. For home computers Windows 3.1 was the largest OS in use and MacOS had a smaller following. Linux had just entered the public consciousness at this time with the release of the first Linux Slackware release. This is the first time most people had ever bought a modem for their computer and dialed out. This era had some horrible teething issues like IRQs being shared or exhausted (if you had too many peripherals) where you could stop your printer or soundcard from working by using your modem. The software was equally bad. Windows didn't come with TCP/IP. One common example was Trumpet Winsock to bring TCP/IP functionality to Windows with a SLIP or PPP connection. The first web browser NCSA Mosaic was release! The web is born! Netscape Navigator, initially release free, then became a paid app. Yes, you had to buy your web browser.
Many regular people would purchase their software tools to get online with this product (IP support, dialer, browser)

1995-1999 - The internet age is upon us! People were buying computers for the first time just to get online. Windows 95 (with the sold separately Microsoft Plus pack) was released which was the first version of Windows to include all the software parts needed to get online (OS, dialer, browser). "Surfing the internet" and "Computer hacking" had now enter the popular vocabulary. BTW, almost no one who hobbied at computing called it "surfing the internet". That ended up being a type of anti-shibboleth. If someone said it, you knew they were a poser. Since regular people were now getting online you ended up having some weird cross-over products like this book. Again, no one that was a regular user would buy this, but when I was working in a retail computer store in the 90s, I can't tell you how many copies of this I saw go out the door with a cheap Packard Bell computer bundle

Decades later I bought an old copy of this. In its pages is a time capsule of what the internet looked like at the time.






