If you can get over the fact that the narrator sounds a little like he collects torsos for a hobby, Wurm Online's
newest trailer has a good overview of what makes this sandbox special. It shows (in fast-motion) the subjugation of a plot of land and the creation of a fortified home before quickly mentioning features like combat and PvP.
Is this the one true sandbox MMO of sandbox MMOs? Give the trailer a watch after the break and let us know what you think.