Two planets found sharing one orbit.

Not the latest of news, but pretty recent. Might just be my ignorance but I'd never even heard of two planets sharing one orbit being possible. (Not saying that it was thought of as impossible, just that I had never even heard anyone mention such a thing.)

http://www.newscientist.com/article/dn20160-two-planets-found-sharing-one-orbit.html

What are your thoughts? The article suggests their orbits are far enough apart that they probably won't ever collide, less the Roche Limit should take place (is that possible for planet-sized objects? I'm a fan of planets with rings. The more debris the better.)

Imagine Earth-sized planets sharing an orbit, even Super-Earth's. Life forming on both worlds would be fascinating, but it'd take the right events on both worlds for that to happen.