General fact: 708 is a number for which we're missing a fact (submit one to numbersapi at google mail!).
Mathematical fact: 708 is the maximum value of n so that there exist 4 denominations of stamps so that every postage from 1 to n can be paid for with at most 12 stamps.
Trivia: 708 is an uninteresting number.
Historical date: December 8th is the day in 1972 that United Airlines Flight 553 crashes after aborting its landing attempt at Chicago Midway International Airport, killing 45.