Of course today using /who #channel every five minutes is the defacto choice because scripts have been doing it for years. The impact on the server is negligible. Even every client doing this repeatedly every 5 minutes would put little strain on a server. And the /userhost approach won't put ANY strain on the server.
Again, you're missing the important point here:
By having mIRC issue its own /who internally, most clients will actually be issuing 2, not 1, /who commands on some interval, because scripts tend to perform their own. Someone on 20 channels performing 40 /who's every 5 minutes (one every 7 seconds) seems like considerable strain to me, especially since, because of SendQ issues on some networks, even issuing a single /who can occasionally flood a user off. This is why mIRC isn't getting involved with /who commands.
Finally, you simply cannot use /userhost here. Using /userhost would pretty much multiply load by 100x, since you have to issue N separate commands for each user on each channel. 20 channels with an average of 20 users = 400 commands every 5 minutes.. that's more than a command a second. And a user who's on just one channel with 400 users (fairly common on some networks) will have the same load. Total users on channels I'm on, on one network, is 1180 users. I'd be flooded off immediately. It's simply not scalable. Sometimes IRC users *do* know everything.
