Effectively, you're describing socket pooling and re-use.. across sessions / tabs / windows. Most browsers already have this in place. :)
Some details on Chrome implementation here: http://www.igvita.com/posa/high-performance-networking-in-go...
Some details on Chrome implementation here: http://www.igvita.com/posa/high-performance-networking-in-go...
Do you think there could be any real-world advantages to doing this at the OS level? On paper it would sound good to me, as it could do this optimization across any application running on the machine.