[manuhabitela]

Also allowed to watch games _live_! Long before streaming videos was a reality.

Ah, the good old days of watching live competition of quake through the game itself, chatting with others basically through the game console.

Pretty cool system.

[dabber21]

I think some games allow this, I remember watching DotA 2 torunaments this way

The game engine, Source, is also using client-server architecture

[Paradigma11]

Also allows maphacks, not cool.