Hope this helps.
from
http://www.dickalba.demon.co.uk/usen.../faq_trol.html
What is a Troll?

a Troll is someone who posts messages in newsgroups with the
deliberate intent of provoking flames or heated discussion or, in the
case of a
destructive troll, an attempt to destroy the group.

There are people who imagine that trolling is always a Bad Thing. Bad
trolling is
definitely a bad thing but I have seen many intelligent and entertaining
trolls. When it
is done properly it can be compared to gently winding people up or
stirring things
for fun, as you would find people doing every night in your local pub.
Where trolling becomes bad is when it is done by someone who has no real
interest in the group's topic and is there purely to hurt or disrupt the
normal flow of
discussion or, as said above, to try to actually destroy the group by
turning it into a
continual flame war.
troll feeds on responses, taking any serious attempts at debate and
turning them
round to feed the fire - this is one of the ways in which a real troll
can be identified.
when it becomes clear that one of these is at work, the correct response
is to post
a short message exposing them as such and thereafter, ignore the thread.
Trolls post purely to get a reaction - think 'attention seeking
behaviour' - and so the
only way to defeat a troll is to ignore it. Forget what anybody tells
you about
engaging them in order to defeat them. There is no evidence of any kind
to suggest
that feeding a troll will make it go away. There is abundant evidence
(and common
sense) to say that they go away when they get no responses.
Therefore, the cardinal rule is Do Not Feed The Trolls.
Of course, when the troll is entertaining, intelligent and harmless, you
can have
some fun by joining in. But if you do this, bear in mind that you will
have become a
troll yourself!)