definitely no.
definitely no.
Yes it does not hurt you in a way unless you link back to it.
You don't have to double post your answer though.
I suggest that you do not concern yourself with pr. Focus on the of quality and quantity of links. By saying quality means to investigate the backlinks of where that link is coming from, as well as who else they are linking to. By quantity, means quantity of anchors are important. Quantity of links will make sure of a good spidering, a good indexing and good traffic.