The inscription says that two men, Erlingur and Thordars, raised a mound on washing day (Saturday). It also lists their fathers, but doesn't say why they raised the mound or for whom. In fact, the last few Runes may be considered "gibberish", they don't mean anything. If you'd like to see this stone, it is housed in Copenhagen, at the National Museum.
While the Runestone is unique in that it is the only stone in Greenland, perhaps the most fascinating Runic inscription from Greenland was written on wax tablets. Around the year 1189, an Icelandic priest named Ingimund Thorgeirsson set sail from Bergen Norway, on the ship Stangarfóli, bound for his homeland. He never arrived. Instead, twelve years later, the wrecked ship was found on the coast of Greenland. Ingimund's body was nearby, frozen. With his frozen corpse the six skeletons of his shipmates were discovered along with the wax tablets, which lay next to Ingimund.
On these tablets, in Runes, Ingimund had written the harrowing tale of how he starved to death. Sadly, I couldn't find any other details about his journey, the shipwreck or what he may have tried to prevent starvation. My contact at the National Museum in Copenhagen assured me that the tablets no longer exist, so those details will remain a mystery.
Still, the fact that he recorded this story is amazing. That he carved it in Runes instead of the Roman alphabet is absolutely intriguing. The use of Runes in Iceland and Greenland continued for more than a century after their conversions to Christianity. However, Ingimund was not the average Greenlander or Icelander, he was a priest in the Roman catholic church. At one point, Norway's archbishop offered him the position of bishop at Gardar in Greenland. Regardless of his reasons for choosing Runes to tell the tale of his demise, the fact that a priest was writing about his own death in Runes makes that inscription Greenland's most interesting Runic inscription.