Desculpe, amigo, mas faltou um item:
No Squid > Access Control > Blacklist, eu utilizo os domains:
#MSN
gateway.messenger.hotmail.com
relay.data.edge.messenger.live.com
gw.msnmessenger.akadns.net
dp.msnmessenger.akadns.net
#webmessengers
webmessenger.msn.com
msn2go.com
ebuddy.com
koolim.com
messengerfx.com
iloveim.com
mabber.com
communicationtube.net
radiusim.com
snimmer.com
SDS,
joaotijolo