What does 711 stand for?

Answer 1

711 is an old term tied to the 7-11 convenience store chain. It stands for "quickie-mart" kind of store (ref. "The Simpsons"). It is also a winning idea or plan (ref. the dice game craps, where a 7 or 11 on your initial roll is an automatic win).

Answer 2

In the US, the hours of operation of 7-Eleven convenience stores was, originally, 7 a.m. to 11 p.m. on weekdays. This was at a time when 'normal' grocery stores were open from 8 a.m to 9 p.m. on weekdays.