At this point in time the share buy back is probably done to show investors the company is confident in it's future and any money spent on share buy back will increase in value probably more than if it is put in any other place at this time. Are they going to be able to make a significant dent in the OS, probably not but the message it sends to the investing world is good.

Considering where the SP is right now thats where I would put my money if I was confident in the future.

All the best,

Steve