I opened it a couple of times to upgrade the hard disk and optical drive. It reminded me of the glimpse I once took as a student of the insides of a Sun workstation. I don't think I could explain this particular feeling to someone who did not see the inside of a Sun workstation—or of an iMac. As a concrete example that does not do justice to the experience the unused screw holes of the factory-installed optical drive I retrieved from the computer had been taped over so that air would not be sucked through the drive lest dust accumulate on the drive's door as years passed.
Unfortunately some functions mostly everyone expects from a computer nowadays is to display e-mail and web pages and this computer is no longer fit for this purpose. This isn't a case of running new software on old hardware. This has never worked but one used to be able to use loved hi-tech gadgets way past obsolescence as long as one avoided the mistake of installing new software on them. For lustra you could keep using the spreadsheet you were used to for accounting or your simple-but-sufficient word processor. Even games kept working!
The problem nowadays is that the option not to upgrade software is no longer available: software more than a few years old ceases to receive security patches. The iMac G4 in question cannot be upgraded past Mac OS X 10.4. On Mac OS X 10.4 Firefox cannot be upgraded past version 3.6. Firefox 3.6 received its last security update in March 2012 and has now joined the Great Repository in the Sky.
Here is an idea for 2013: how about making software that works? Of course it would not automatically adapt to new protocols but as long as the user was satisfied with the old ones this software would simply keep working. It would not have to be constantly updated with security patches because it would have been made right the first time just like hardware sometimes is.
I would not want to give the impression that I am unfairly picking on the fine developers of Firefox. Firefox 3.6 continued to be maintained long after Safari for OS X 10.4 had ceased to receive security updates. In fact the TenFourFox project a maintained variant of Firefox for precisely the kind of computer I took to the basement is a testament to the power of Open Source Software. Unfortunately there is no Adobe Flash support in TenFourFox and I fear that this might complicate the life of a computerwise-unsophisticated user.
Acknowledgements: besides selling me his computer Damien Doligez officially owned the first OS X-able mac I used as a PhD student. Harry McCracken suggested to liven up this post with a picture. Gerhard Piezinger photographed an iMac very much like mine and I used his picture.Pascal Cuoq