It's a new exoplanet! It's the first to be classed as a "mega-Earth"! I am unreasonably excited!
It's about twice the size of Earth and 17 times as massive. Like Earth, it's made of rock and water. If it has sufficient atmosphere, it may be habitable. It's also predates the earliest stage in the universe's development in which it was believed that rocky planets could be formed, so that model is going to need some tweaking. It also throws the door wide open for more mega-Earths!
Kepler-10b, another planet in the same solar system as Kepler-10c, orbits their star every 20 hours. For some reason, I find that incredibly beautiful.
I really don't have anything to add here. Pretty much everything I have just told you, apart from my enjoyment of it, was lifted from the original article. I just really love exoplanets.