Grimes and Blood Diamonds last collaboration, 2012’s “Phone Sex”, was that year’s greatest hit that never was. The song hit the same euphoric touched on by Rihanna and Calvin Harris’s inescapable 2011 hit “We Found Love” without hitting the heights of that Rihanna mega-hit. Now, Grimes has released another collaboration featuring production from Blood Diamonds, this one called “Go”, which turns out to be a song penned for Rihanna that somehow didn’t get picked up by the pop princess. “Go” does indeed sound massive, and is a late but worthy contender for song of the summer, no matter ones definition of what a summer song should be. Because regardless of whether or not “Go” received radio play, this will be the track you wish was coming through your FM transmission these next few months. For Grimes, her unapologetic embrace of the mainstream has resulted in one of her most instantly appealing songs yet. Poptimism isn’t so bad after all.