Why is @Twitter butchering URL's?

I and many of my Twitter friends have noticed that Twitter is now doing strange things to URL's that make them unusable in subsequent replies, tweets, and retweets.

Needless to say, this greatly hampers the Twitter 'conversation'.

This is yet another example of Twitter shooting itself in the foot.

Does anyone know if this is accidental or intentional, and if intentional what the geniuses at Twitter are trying to accomplish by it?

Is it another step in Twitter's war against traditional, or classic, retweets?