Sometimes when somebody is online and has a GL window open,
he or she may not see the pop-up alert for attacks (trap trigger message) or invasions (planet invasion alert),
because s/he is not watching at the GL window at the moment.

A sound effect (siren, boom, whaaaam, slam, etc) with pop-ups would help users to have more active GL experience.
This would require an additional sound effect on/off button as well.

+1
like the idea tho sometimes it's 10 minutes before i get the notice at all this idea is good.

The problem is that after x amount of minutes, the game stops talking to the server until you remind it to by doing something. If it is after x period of time, the only things you see are what's on the ships log.