I think the point was that full mail ids are often different to
login IDs, and this makes fingering by name a problem. I login
as tjc but my mail ID is rewritten on sending to T.J.Chown. Also,
from our site we (try to) hide all hosts and as a result fingering
someone here at ecs.soton.ac.uk will fail because we don't allow
logins on our mail/news gateway machine. So if you want an open
finger service I guess you give up a little "security".
Having said that, running icsi-finger internally is rewarding
Tim