Even with the net being that limited many of us forged our first attacks; often just to mess with our friends but sometimes also to punish an adversary. It was all in good fun back then and no real damage was intended. It also gave my friends at the time and myself a lot of new experience coding because it is always more fun to have a goal when writing a script or program than to just do "Hello World."
Ok, so I'll disclose my personal favorite: Hanging out on EFNet IRC a lot, I was always attracted to the misfits called "Operators" which actually ran (still do) the network and hanged out there. Many people (including myself) have tried and failed to hack that channel and kick all the operators out as a badge of honor. Knowing I didn't have the skill at the time to write a bot to do it, I took a bare-bones approach and read the IRC RFC looking for loopholes.
My Friends and I were so intent on hacking IRC we experimented with creating our own network of servers just to see how they operated. While doing that I had an epiphany that there was no limit on how many people can be listed in a -o message. The only limit was in the client, which was typically four.
So, I convinced a friend who was an IRCop to give me an O: line to test my new server. I then commenced to login via telnet masquerading as said server and de-op nearly everyone on #twilight_zone. The only thing which prevented my success was I was typing the list by hand and someone joined at the same time so didn't get de-opped. I was banned forever from that channel for managing to de-op a few dozen people in one line, but I still felt successful for pulling off something a regular bot could never do by my own hands in a telnet session. The only reason I wasn't banned from that network forever was out of respect for the research and attention it took to pull off the attack. I also had no idea what social engineering was back then but it was key to getting server-level access.
So what are your early benign hacks, folks?"