[troad]

> Not something I've ever seen (or noticed, at least) or used.

It's all the icons next to the clock, placed there by applications that run in the background but need occasional interactivity.

It's the thing at the bottom right of every Windows since Windows 95, and the top right of every Mac since Mac OS X. KDE has always had it in the Windows position. Gnome had it in the Mac position from Gnome 2 (2002) until recently (Gnome 4?).

Something that every desktop OS considers important enough to show, except Gnome, which insists your computer is a bad iPad for some reason.

[ErroneousBosh]

I guess you'd have to have used Windows to miss it then. I don't understand why it would be important.

Why would I care about what the network is doing?

[troad]

The network icon usually contains controls for connecting to and disconnecting from networks, which are obviously useful.

> I guess you'd have to have used Windows to miss it then.

I don't understand what you mean by this. For most of the past 30 years, every major OS had something analogous to a system tray. Win, Mac, KDE, Gnome all had icons next to the clock, that gave access to software running in the background or system functions. Virtually all still do, Gnome (apparently?) does not.

I find it deeply implausible you've never seen or interacted with a system tray.