Quoting Paul Ficinski <spf(_at_)fairymouse(_dot_)com>:
Well *you* used a webmail client to write your email...
Under duress, because my employer blocks all useful ports but does not have a
policy that bans use of personal email. If personal email were banned, I'd
stop. As is, by putting in place a technical roadblock instead of an
appropriate policy roadblock, they push me to spend 3x the time I would use
with a good tool interacting with webmail.
Webmail is popular with some providers - take hotmail to be one very
obvious example.
It doesn't matter what's popular with a provider -- it matters what clients WANT
to use. Webmail is popular with Hotmail users because it used to be all they
had, and it is all they really promote.