Has anyone figured out how to identify the unique page of each separate Safari Web Content process with Safari 7/Mavericks?
This is not an ideal solution but a quite good working workaround. 

Open Safari then go to Preferences. 
Activate the Debug option (Show develop menu in menu bar)



EDIT: Instead of activating the develop menu, you have to open a terminal and activate the debug menu with defaults write com.apple.Safari IncludeInternalDebugMenu -bool true

Thanks @Collin C.

You will find the option Show Web Process IDs in Page Titles under Debug > Miscellaneous Flags



If you open the Activity Monitor now, you can see the Web Process IDs to the corresponding websites.



I hope this is helping you.