The most popular export from the Moon and Mars will be information. Just basic live streams from daily activities with monthly subscriptions would probably be quite popular.
It'll be really popular for maybe 6 months, 1 year maximum. After that, everyone will lose interest.
We've already seen this before with the Moon: when Apollo 11 landed on the Moon, everyone in America (and probably all around the world) watched in on TV. With subsequent missions, no one cared, except when there was a big problem with Apollo 13 and the astronauts' lives were at stake.
...and every day parents around the world are making more new fans than ever.