AOL != internet
AOL is the legacy of the era of "Content Networks" or whatever they were called. AOL was the ugly duckling, with Compuserve having a hell of a lot more users back then, and they already had a Windows client by 1996. There were far more users using Compuserve for Internet than AOL users. The rest of the masses were actually using local ISPs, you know, the zillion dialup ISPs that used to exist before they were all Blockbuster'd into oblivion by AOL.
While Win 3.1 was a pain to get on the internet (we depended on Trumpet Winsock or similar apps), Win95 actually came with an internal TCP/IP stack, or at least one that worked well enough to work out of the box. So no, the iMac wasn't the first one with internet connectivity; what it *did* have was the ability to work out of the box without fumbling for a zillion cables; just plug in keyboard, mouse, phone line and power. Voila!
However, I think that by the time the iMac came out, the Internet boom was already in gear, and the most popular FPS of that time (Quake) having TCP/IP support, which incidentally also started the whole FPS modding fad. It was possible with Doom, but during Quake's lifetime you could find all the good modding tools on the 'net, and could publish your mods on the Quake-related sites. Ah, the days...
Hell, it was probably Quake the one that got kids on the 'net. 64 player deathmatches or CTF sure beats 2-player modem games!