The ability to see who you have contacted with an open job posting or resume submitted through your website/app! I wish it was possible when sending out emails via my email address as well but at least we can identify which resumes were sent from us versus others (i don't know if this works).
This allows me not having to go back into each individual application manually because now i've got all their info saved within one place so its easy going forward once they get hired then just add them onto payroll etc.. Its great knowing how many people applied vs actually getting someone interested enought o come visit about employment opportunities!!