This handy greasemonkey/userscript no longer works (since battlelog update):
The functionality is awesome though, and might make sense to incorporate into bblog.
Basically, it allows listing all platoon members currently playing, even non-friends.
This was requested few months ago and rejected.
The reason is that this script do a lot of request to battlelog server to get this things out.
BBLog doesn't support things that fires a lot of extra requests to battlelog servers.