Actually, when you write a letter to someone, it DOES NOT always remain
the property of the writer. Some companies/individuals/management will
actually assume that any material submitted to their list will become
their property. (At least that's what my experience in law tells me.)

(It doesn't apply to me since I write all the list materials myself, I run
an announcement list.)

You may come across material such as this:

If you do send us any creative materials, including creative suggestions,
ideas, notes, drawings, concepts or other information or if you transmit
to the Site by electronic mail or otherwise, communications including any
data, questions, comments, suggestions, or the like (collectively, the
"Information"), the Information shall be deemed, and shall remain, the
property of CBS. None of the Information shall be subject to any
obligation of confidence on the part of CBS and CBS shall not be liable
for any use or disclosure of any Information. CBS shall exclusively own
any now known or hereafter existing rights to the Information of every
kind and nature throughout the universe and shall be entitled to
unrestricted use of the Information for any purpose whatsoever, commercial
or otherwise, without compensation to the provider of the Information.

(taken from CBS television network's homepage)

What it effectively means is that whoever that "owns" the mailing list (be
it the moderator, the postmaster or the people who own the machines that
distributes the list) *MAY* own the material submitted on it. (I emphasize
the *MAY*.)

While it probably doesn't matter if the mailing list is about jokes or
research into the behaviour of chihuahuas, these issues could be crucial
on lists that discusses things which may have commercial value, I think.

Juntung Wu (JT)

PS Just to say that I have not been working in the legal area for a long
time and this is just my opinion. Check with your attorney for full
details. Sorry to make this statement: just to protect me :(