I didn't know Earthbound even existed until the Wii came out and suddenly people were demanding that it be brought to the VC.
All I know is:
1. It's an RPG that's considered a breakthrough for the genre
2. It stars Ness and Lucas, who are kids with superpowers controlling fire, ice, lightning, and "plus"
3. It was released for the SNES, and was not initially successful
4. It is known in Japan as MOTHER
5. It's had sequels and has been released on multiple systems
6. Ness and Lucas have been featured in the SSB series with Earthbound-based stages and music
7. The powers are called "PKs"