[codgercoder]

Let the unintended consequences begin! I always found this change suspect; a frequent rationale was that the rest of the world does it this way.

[eurleif]

The rationale I've heard is that "first to invent" is not always easy to determine, which adds overhead. Note that prior art is still valid. If you publish your idea, that can invalidate someone else's patent. But an idea in a private notebook isn't enough anymore.