U-matic is probably the first video tape format, if you take popularity and market share into account.
http://en.wikipedia.org/wiki/U-matic
Late 60s, early 70s -- mostly for recording, production.
Not renting or home market. No studio releases or anything like that. That didn't come until Betamax and VHS.
It was replaced by the various Betacam versions in the past 20-25 years.
Some rare things pop up on U-matic from time to time.