[Savannah-cvs] [SavaneTasks] (edit) reintroduce paragraph about DNSBL

[Beuc]

??changed:
-Problem spam on Savannah comes not from email spam but instead in the form of 
web posts.  Currently there's a simple "type 421" captcha-style box for 
anonymous posters.  This seems to work well.  But spammers now tend to create 
user accounts anyway.  After creating an account there is no longer any 
automated blocks to posting and this includes posting spam.  A voting mechanism 
to remove spam exists.  Project owners can vote spam out in one vote.  Others 
require multiple votes to hide posted spam.
Problem spam on Savannah comes not from email spam but instead in the form of 
web posts (aka spamdexing). Currently there's a simple "type 421" captcha-style 
box for anonymous posters.  This seems to work well.  But spammers now tend to 
create user accounts anyway.  After creating an account there is no longer any 
automated blocks to posting and this includes posting spam.  A voting mechanism 
to remove spam exists.  Project owners can vote spam out in one vote.  Others 
require multiple votes to hide posted spam.

Other mecanisms are implemented in Savane, and used at gna.org in particular, 
but are not used at Savannah.
They include so-called "IP blacklists" (aka DNSBL), but they are blocking 
legitimate people from login in,
because black lists tend to be more and more "white lists"
(that is, wide IP ranges are blacklisted and people need to do some work and 
prove their good will to get unlisted,
which is essentially whitelisting). DNSBL is often used for e-mail spam, and 
not so many people have their own
mail server, so false positives are limited, but when it's used for spamdexing, 
more legitimate people are impacted.

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