This is a Wikiversity Learning by doing unit that encourages participants to Learn Linux. If you are new to Linux, find an older discarded machine and try it out. People throw away perfectly good computers all the time just because they are virus-infected or no longer run the latest and greatest non-free OS.
Debian runs on all sorts of computers from tiny laptops to giant servers. It's easy to install on both modern machines and presumably "obsolete" older ones. "Each new release of Debian generally supports a larger number of computer architectures."
Ryan Murray of Debian operates the build daemon for the i386 release at "Lenny". Using the debian-50x-i386-netinst.iso works fine on something like a Dell® laptop or an older Compaq® desktop PC. The Network install method is good because it allows you to get up and running quickly, provided you have a reasonably fast connection and a dedicated hard disk. Accepting the defaults works for the typical user. The net-install CD detects hardware quickly and thoroughly and presents you with reasonable options.
It's important to understand the community-driven nature of Debian. Debian's default answer for participating in their "Configuring popularity contest" is <no> but it's a good idea to change that default to <yes>. (opinion, of course)