This is  either a feature request or a request for discussing
solutions to the issue of known comment spammers against XWiki
installs.
There's known spammers like davycrokkett(a)hotmail.com (see
http://www.nielsmayer.com/bin/view/XWiki/DavyCrokkett ) which have to
be managed and curtailed for any XWiki install enabling comments.
During registration, it would it be nice to check sites like
http://www.stopforumspam.com/ and prevent registration emails from
going out to known comment spammers.
For example, the aforementioned spammer is listed at
http://www.stopforumspam.com/ipcheck/111.243.227.227
suggesting Current country of origin:    Taiwan, Province of China
Date    IP Address      Username        Email
1-Jul-11 07:31  111.243.227.227 coseteene       davycrokkett(a)hotmail.com
30-Jun-11 18:29 111.243.227.227 Assusypesound   davycrokkett(a)hotmail.com
30-Jun-11 13:43 111.243.227.227 Impuppota       davycrokkett(a)hotmail.com
30-Jun-11 11:22 111.243.227.227 Biordaccoma     davycrokkett(a)hotmail.com
30-Jun-11 07:01 111.243.227.227 rooviskitte     davycrokkett(a)hotmail.com
29-Jun-11 23:59 109.230.222.175 Beethyemegree   davycrokkett(a)hotmail.com
29-Jun-11 22:49 111.243.227.227 Kneefshes       davycrokkett(a)hotmail.com
29-Jun-11 13:59 111.243.227.227 seltencarne     davycrokkett(a)hotmail.com
29-Jun-11 13:31 111.243.227.227 inigneedync     davycrokkett(a)hotmail.com
29-Jun-11 11:50 174.142.132.203 Beethyemegree   davycrokkett(a)hotmail.com
29-Jun-11 11:50 174.142.132.203 phorilmiplism   davycrokkett(a)hotmail.com
29-Jun-11 07:53 111.243.227.227 Agergeevame     davycrokkett(a)hotmail.com
29-Jun-11 05:56 111.243.227.227 Atomnegmess     davycrokkett(a)hotmail.com
29-Jun-11 05:50 111.243.227.227 Impuppota       davycrokkett(a)hotmail.com
It would also be interesting for such flagged users to return a list
of associated IP's (such as above) which could be blacklisted as well.
I guess the correct solution would be to use
http://extensions.xwiki.org/xwiki/bin/view/Extension/Social+Login but
then the spammers would just end up getting twitter, facebook or
foursquare logins and use those instead of hotmail accounts.
-- Niels
http://www.nielsmayer.com