[roryirvine]

They may have been introduced in Windows 95, but they didn't actually become particularly common until years later. They weren't originally intended as a long-term feature and, in Win 2000, Microsoft started recommending that people use custom Control Panel objects or MMC console snap-ins instead. But the MMC wasn't an option in Win98/Me and, by the time MS finally managed to produced a consumer variant of NT, use of the system tray had become entrenched.

I'm not sure what Windows is like these days, but in MacOS they're patently absurd. My corporate Mac laptop has twelve of the fucking things, and I've never actually had genuine need to click on any of them (and 5 of them are from Apple and so of course use 4 different corner radii between them - the 3rd party ones are at least a little more consistent).