I'm looking for information on the adoption of voice mail from when it
was created to date.  When was voice mail introduced, what did the
adoption curve
look like year by year (ideally with subscriber numbers or units sold)
and what were the catalysts for growth.

Hi, I'm 42 now and therefore old enough to remember the introduction
of voice mail, or 'the answering machine'. A little background. I have
an uncle who's roughtly 15 years older than myself, and he's always
been an early adapter of new technology.

In 1973 my parents drove our family (in a plymoth stationwagon) from
New York to Kansas where he was stationed in the army. When we
arrived, we stopped at a pay phone, and my parents let my 13 year old
sister call him. She got the 'answering machine' (a first ever), and
was so disoriented by this new gadget that all she could think to say
was 'we just got here' and hung up. To which my younger brother and I
delighted in teaseing her.

Not that this answers your question, but just an anecdotal version of
some initial impessions.

Patrice