BDB has had a commercial licence available for a long time, this move just closes a loophole that people were exploiting to use BDB in non-free software without contributing back.
Additionally, to the people saying 'oracle are only doing this to make money', this is one of the ways you are supposed to make money/fund the development of free software. RMS talks about it here: http://www.fsf.org/blogs/rms/selling-exceptions
I consider selling exceptions an acceptable thing for a company to do, and I will suggest it where appropriate as a way to get programs freed. -- RMS