It's not known how digital videos were transmitted on the internet, As far as I know, They've been on FTP servers and Email. Video files started appearing on the World Wide Web possibly on 1992 or 1993. They've appeared on various websites ever since, Online video on the web became popular, it usually downloads videos on common files such as MPEG, MOV and AVI, Prior to modern video sharing like YouTube, Video files had became popular on the web as far as we know it. Do you remember any video downloading websites prior to YouTube?