Subject: How long will my posting stay on the Usenet news?

27. *****

 Q: How long will my or someone else's posting stay on the news?

 A: There are some Usenet news related questions which cannot have a
unique answer. This is one of them.
   Each site (your host) receiving the newsfeed can define how long
a news posting is kept before it is deleted, that is before it
expires. The expiry can even be made to vary at a site depending on
the newsgroup. In fact this is fairly common. The default expiry
lengths at the various sites are influenced by many factors like
local policy, the relevance of the newsgroup, the capacity of the
local newsserver computer, and so on.
   The current Usenet news volumes are staggering. This puts
pressures on many sites to use quick expiry spans. Since the news
travel at different speeds from the different parts of the net, and
parts of the net may occasionally be down along the feed, the news
arrive at differing lags. Unfortunately this means that at worst
some newspostings can even have expired when they finally arrive.
   If you look at the header of a news posting you will note an
"Expires:" line in the header. This can be used to TRY to alter the
expiry. The format is "Expires: Sun, 14 May 1995 10:00:00 GMT"
without the double quotes. Please don't use this feature unless you
have a very good reason and know what you are doing. Also note that
many hosts override the users' expiry redefinitions.
--------------------------------------------------------------------