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If they killed their bridge to freenode entirely, rather than just unlinking their own rooms, it would zap a whole bunch of freenode users. Their bridge also kicks users from bridged channels and disconnects them from IRC after 30 days of not sending messages to any of them.
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Once that churn happens, the remaining freenode users are probably largely just going to be people leaving their IRC clients / bouncers running without paying attention or bothering to disconnect. I'd be more interested in some kind of activity metrics than the user count.
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