Active users vs just online

A server currently shows a number of members online and a total number of members. Can there be an optional and/or adjustable means of measuring the number of active members? For instance, as a Server admin, I could enable active member tracking and specify that an active member is someone that has posted anywhere in the server in the last X number of days/hours. Then larger community servers can see not just how many members are online, but how many active users they have and have the option to show that on the join server banner instead of just the online number. This will help in recognizing if you're joining a server that actually has people involved in it or just a bunch of them in it that are online but never actually talk.
A step further is that this can also benefit Admins in gauging where they need to focus moderation efforts if there's a lot of activity in channels besides a general chat channel. That and also in recognizing which parts of the server could be cleaned up or refined that aren't seeing that much activity at all.