Tom Truscott and Jim Ellis (sez Wikipedia) developed Usenet (on top of UUCP) in the 78-80 time frame. The folks who did Kermit also probably deserve mention as

Tom Truscott and Jim Ellis (sez Wikipedia) developed Usenet (on top of UUCP) in the 78-80 time frame. The folks who did Kermit also probably deserve mention as that was quite important as modems became affordable and networking spread.