Users need the ability for Linux firewall to filter packets based on what Application they are originating from. This ability is present in Mac and Windows firewalls, but not Linux.

For example, users would like ability to open Port 80 for Firefox, but keep Port 80 closed for other applications.

This ability enhances Privacy & Security of the user but also helps to better inform the user about the comings and goings of internet traffic and what application/s are causing the traffic.