How did Greenland get its name?

Answer

The story of it being just clever advertising is widely told and believed, but it is a myth. At the time that Greenland was discovered, the Earth was a bit warmer and southern Greenland actually had green meadows and could sustain villages of Norse settlers and their cattle, sheep, goats, horses, etc. The name was actually an accurate description of the land at the time.

Since that time the Earth had cooled down some and the ice sheets advanced, forcing the Norse settlers out again.

A similar history befell the early Norse settlers to "Vineland" (North America). When they arrived the weather was warm enough to grow grapes. Ultimately global cooling drove the Norsemen back to Greenland and then Iceland. The colony in Iceland was well established by that time and survived.
In Norse legends written in the 12th century and later, it is told that Eric the Red explored the southeast and southwest coasts of Greenland in A.D. 983-986 and gave the country its name because people would be more likely to go there if it had an attractive name. Greenland was warmer in the tenth century than it is now. There were many islands teeming with birds off its western coast; the sea was excellent for fishing; and the coast of Greenland itself had many fjords where anchorage was good. At the head of the fjords there were enormous meadows full of grass, willows, junipers, birch, and wild berries. Thus Greenland actually deserved its name. Another attraction of Greenland was that Iceland and northwestern Europe, including England, had a grievous year of famine in 976, and people were hungry for food as well as land.