According to the Simple Explanation's story of creation, there are torus-shaped eddies of gravity and energy scattered throughout the universe, ranging in size from tiny to gigantic. This Laniakea would be one such example of a giant vortex that grabbed interstellar particles from the earliest expansion and pulled them into this local system. The toroidal vortex for this large system can be seen on the surface.
Here's a short animation of the cluster provided by nature video. It's stunning!
According to James Cave's article in Huffington Post (9/5/14),
"Until now, the Milky Way was believed to be one galaxy in the 2,000 that make up what's known as the Virgo "supercluster." But as the new map shows, the Milky Way's 100 billion stars are actually part of something 100 times bigger: a supercluster of galaxies astronomers have christened Laniakea, meaning "immense heavens" in the Hawaiian language.