My first contact with Slackware was when I bought a book in 1996 to learn more about Linux. I had some previous knowledge about Unix from working with Minix, Sun Workstations and other Unix-like systems at work, so I knew 'the basics' but was intrigued by the possibility to have a Unix-like operating system at home.
In the bookstore I chose a copy of "Slackware Linux Unleashed" as it seemed to be very complete, from the basics to advanced administration. And this book came with a CD that included 'Slackware 96', also known as Slackware 3.1. I installed it without any problems on one of my computers and started learning through discovery.
Once installed, I started looking for more information and discovered about the subscription system, where newer released would automatically be sent to me at a reduced price. Through this subscription system I received Slackware versions 3.4, 3.5, 3.6 and 4.0, all in nice boxes with 4 CDs.
For many years I used Slackware as a second operating system, together with Windows. Some time in 2006 I switched completely to Slackware at home. My kids still use Windows on their desktops, since they like playing games.
Currently I have five systems running Slackware at home: two using '-current', my wife's desktop and a server / firewall running 13.0-stable and one on 4.0
This last one is my old 486 headless laptop (with a broken screen) that I just use to show that Slackware can run on a system with 20MB of RAM and a 50MB partition on a 300MB drive. It doesn't run X though ;-)
I also have several virtual machines installed running Slackware 13.0 & -current for testing purposes. Usually several of them are running at the same time. I use these to build and test packages, as they always fall back to "snapshots" so that they continue clean, even after installing several programs.
All in all, my network (real "iron" + virtual) usually has more than ten machines running at the same time, in a mix of Slackware, ArmedSlack, Slack/390, and even Windows...
After meeting some of the members of the Slackware team in Brazil (Alan, Erik, Robby, PiterPunk), I reinstated my subscription and have already received the original Slackware 12.2 and 13.0 DVDs.