There's a somewhat semantic discussion going on in the blogosphere in regards to people who once called themselves "liberals" parting ways with that term (due to the negative connotations its taken on after years of derisive use by Republicans) and embracing the term "progressive" instead. The terms are not quite interchangeable, but I think most people who only have a cursory familiarity with the terms wouldn't sense a yawning gap in meaning.
However, a fight has broken out in regards to the historical meaning of the term "progressive" and the views the original Progressives expressed in regards to eugenics.
Thankfully, Jane Galt tackles this and makes an important distinction.
Update: Julian Sanchez has a very smart take on this entire discussion over at his place.