I seem to recall at one point it was the one-click-install (more or less) Windows program that actually let / made it easy to pull headers without pulling entire messages. A relative was on a slow modem, and I trained them in this feature so that they could delete the majority of their nascent spam deluge from the sever without incurring the hit of downloading the entire messages.

(Spam filtering options started becoming commonplace / an option for them not too long thereafter.)