Read the official story (let's hope the media actually has the facts right): http://www.reuters.com/article/2011/08/25/us-planet-diamond-idUSTRE77O69A20110825
For most of my life I've been fascinated by astronomy and - every so often - I get back into it and read voraciously for a couple years to get back up on what's going on. Not up on the latest now, but naturally this story of a potential 'diamond planet' in a pulsar system caught my eye.
Now this planet orbits a pulsar (which is the remnant of a star gone nova) in a very tight orbit so...what if the original planet-star system was akin to a 'hot Jupiter' that we have found to be rather common in our galaxy? (A 'hot Jupiter' is a type of gas giant that orbits its star very tightly, some are closer to their stars than Mercury is to our Sun).
The scenario I'm picturing is that the star went nova with a hot Jupiter close in (or a gas giant relatively far out that then spiraled in). The nova blew off the thick atmosphere of the gas giant (essentially hydrogen and helium with other gases thrown in for spice), leaving the core intact. If this is the case, then this 'planet' - aside from potentially supporting the theory of 'diamond rain' in gas giant atmospheres - could also be an opportunity to directly observe the core of a gas giant planet which is something we normally would have no means of doing.
Of course, I'm sure the blast would have affected the core in some manner so it's not like looking at the core of an actual gas giant, and we have no way of knowing what the original planet was like in terms of mass and composition. It could have even been a brown dwarf, rather than a partner star or gas giant planet. Still this object could offer some information about what the deep interiors of planets like Jupiter, Saturn, Uranus, and Neptune are like.
This is all highly speculative of course, but it's exactly the kind of thing that has always fired my imagination about astronomy!