Picking up the phone and realizing you'd probably just disconnected someone in your house.
PC Computing magazines with lists of "top links" and demo diskettes for new or upcoming games.
Netscape Navigator.
Opera (browser).
Having multiple messenger apps (well, "programs" in the parlance of the day) running simultaneously -- like ICQ, AIM, MSN, Yahoo...
LAN parties.
MUDs.
Morpheus and WinMX (after Napster went under and later turned legitimate)
WINAMP - IT REALLY WHIPS THE LLAMA'S ASS
(edited to add🙂
Stacks and stacks and stacks of floppies.
Later, stacks and stacks and stacks of CD-Rs.