It's incredibly difficult to express just how massively popular E.T.: The Extra-Terrestrial was during its initial run, so I'm going to steal someone else's words to do that for me.
Richard F. Dickson, writing on his blog The Daily Rich:
E.T. wasn’t the kind of blockbuster like we see today, ones that make over $100 million in their opening weekend, blitz their way to $200 or $300 million in a week or two, and then plummet down the charts when the next big thing comes along. E.T. opened in June of 1982, and ranked no worse than #2 in weekend box office totals all the way into October. It didn’t drop out of the Top Ten until February of the following year, and was managing to creep back into it as late as May 1983. I mentioned the frenzy over Jurassic Park in 1993, but while that was a sort of redemption, E.T. was a coronation. People didn’t just think this was a great fun movie, they loved the thing. There was genuine anger in some circles when it lost the Best Picture Oscar to Gandhi; I remember our local movie critic titling his Oscar commentary, “Hollywood Snobs Turn Oscar Into Peace Prize.” This adorably ugly little alien tapped into the feelings of everyone from kids to adults; we even managed to drag my grandmother to see it. It was that most sought-after of Hollywood commodities: the four-quadrant film, one that appeals to everybody. And in 1982, it sure seemed like everybody went to see it.
Not only did they go see it, they bought the t-shirts, lunchboxes, toys, trading cards, and hot mitts.
Consciously or not, Spielberg was taking a page from George Lucas' Star Wars playbook by creating a character with nearly limitless merchandising potential.
Here are some rather creepy talking toys from the '80s:
Some rad Buster Brown E.T. shoes:
Best of all, though, is this commercial for the ill-fated E.T. video game for the Atari 2600, which was rushed through development in just 5 weeks (rather than the months typically required) to make the Christmas season production schedule. The game was a massive flop and thousands (if not millions) of copies were reportedly destroyed in a mass burial of unsold Atari cartridges in 1983.