If I recall correctly, the way pirates work is that there are a certain number of AI groups spread out between sectors the players have explored, and they wander until they run into a player and get destroyed, at which point a new group spawns.
So, if you aren\'t seeing pirates spawn anymore, your server admin needs to increase the maximum fleet simulation setting in the server config to offset the fact that your large playerbase has (presumably) explored a lot of space and therefore thinned the AI groups out.
There\'s also an issue with AI traders getting stuck when they\'re unloaded after passing through a sector with an active player in it, and since traders count as an AI group it\'s theoretically possible for enough of them to get stuck to fill out the group limit and stop pirates from spawning completely.