Hi John, 60 edits a minute sounds high, and probably faster than most of these sessions run at, but not if it is as I suspect, calculated every few seconds. So if the tutor says "all save now" and ten people hit enter simultaneously the attempted editing rate is briefly rather more than 1 per second - hence the throttle kicks in and the tutorial collapses in chaos with several students getting throttling errors at the same time. It would be nice to think that the WiFi we used was going through the same IP as the rest of the British library and that we merely lifted the normal editing rate above 60 edits a minute, but I suspect that the rate is calculated rather more frequently than every minute. Presumably established users of some sort are whitelisted through this? If so it could explain a longstanding Cat a Lot problem. I frequently use Cat a lot to categorise images on Commons and my personal editing rate there has gone far above 60 edits a minute, however I'm pretty sure I'd be on any commons whitelist. But other editors have complained that Cat a Lot doesn't work for them and mysteriously hangs or fails, Is it possible that this throttling feature could be the cause of that problem as well? If so perhaps it would be a good idea to analyse some of the recent incidents where this feature has kicked in, see how often it disrupts goodfaith editing and how often it disrupts badfaith editing that wouldn't have triggered the edit filter. Maybe this was once a net benefit, but with the edit filter dealing with most badfaith editing, and increasing amounts of editing workshops and tools like Catalot, perhaps this feature has transitioned from net positive to net negative? Alternatively could we have a process where we can whitelist the IP Addresses of places where we are running training sessions, and put note on http://commons.wikimedia.org/wiki/MediaWiki_talk:Gadget-Cat-a-lot.jsexplain… how to spot if your editing has been throttled and how to get yourself Whitelisted WSC