what: telling should be possible to invis players
why: it is possible to use channels for communication anyway (all of them
party/ss/public) - so why is direct communication not possible ? I'll give an
example where this is useful: I am invis (and newbie) and standing before a
big monsie. As soon as I become visible I will be only few seconds away from
death. It would be convenient to be able to negotiate a summon a way from the
monsie (preferably without spamming channels).

tell &foobar this comes thru invis

Also see set for option to enable receiving tells while invis.
('set allow_offline_tells on')

and how did that answer the question?

Umm, He explained what to do to allow tells to someone invisible, both the
syntax for doing so, and the set option required if it doesn't work?
Personally I was going to reply with, you already can, dipshit, but Twomi is
more cuddly than I am.