Last Logged In
I'm suggesting a last logged in date for alliances, e.g. it states a member's last login date next to their name on the member list of the alliance.
Some Benefits:
~Tells you who's inactive
~No hassle of mail active checks
~Good for active alliances
Drawbacks:
~Bad for inactive clans who have strong inactive members
~Tells spies a lot about the alliance
Questionable thoughts:
~Should only vices and the leader see the last logged in date?