Dont want to /whois someone 3 times when they join the same 3 channels your on either.
A cheap and nasty counting down flag would fix it i guess..

on !*:join: if (!%wioj. [ $+ [ nick ] ]) { set -z %wioj. [ $+ [ $nick ] ] 5 | whois $nick }

Could do better by checking whois responce etc, but its alot more code.