[tor-talk] Why so may exit node IP addresses in the TBB?

[blobby at openmailbox.org]

Has the TBB changed the way that IP addresses are allocated?

It used to be that, if you opened five sites in TBB, all five would use 
the same exit node. Now it appears that each of the five sites has the 
IP address of a different exit node.

Is this a new policy? What is the purpose?