Any thoughts on why he'd choose to do this when he is focusing on Square? Could it be that he disagrees with what's happening with Twitter and wants to steer it in the direction he wants it to go?
Is it a great PR response? It seems to me that a move like this helps solidify the #dickbar as a failure, and shows the company acknowledges it needs to fix the direction (which they have not been willing to state thus far).
Who knows what motivates a person, but strictly from an opportunity perspective, Twitter is a more certain outcome than Square. If NFC on the phone takes off, then Square technology may soon become antiquated.
This move certainly doesn't bode well for Square, though.
It's important to note that most of what Square brings to the table is not hardware. It acquires merchant transactions and manages payment risk. Square can simply support other hardware technology, but their focus is on the merchant side.
I think he just loves the product. Based on some of his recent interviews, Twitter is something he's been thinking about a long time and is based on things he's worked on his whole life (dispatch, maps, cities, networks etc.)