ContextSmith has an intuitive way of tracking email opens/open rate and displays that information succinctly in my Gmail. This makes it very easy to see who is interacting with content and how often. Review collected by and hosted on G2.com.
I've noticed that I "log-out" rather frequently with chrome extension and it sometimes can take a decent amount of time to log-in. The screen remains blank for a random period of time and I will have to refresh my browser a couple of times in order to get things synced back up. Review collected by and hosted on G2.com.