Defining the Drake equation: how common are rocky planets?

A new imaging technique allows visualization of a very large rocky planet orbiting a red dwarf:

Scientists spot a new Earthlike planet - Space.com - MSNBC.com:

The planet and star are separated by about 2.5 astronomical units.

The finding means planet hunters are one step closer to detecting their holy grail: a habitable Earthlike planet that can sustain liquid water and support life.

The distance sounds comparable to our asteroid belt. I wonder if that's coincidental.

The significance of the discovery may be the proof of the microlensing technique. We probably have years to go before we can begin to put more meaningful numbers into the Drake Equation, and thus constrain the solutions to Fermi's Paradox.