Per the consensus in the above link, please enable the Abuse Filter extension on English Wikipedia.
To avoid doubt, the following needs to be done wrt configuration and code review:
A live demonstration is available at http://wiki.epstone.net/test, but the code will require review.
Assign the following permissions to all users ('*'):
Assign the following permissions to a dedicated group 'abusefilter':
Assign the following changeable groups
SYSOPS can add/remove the abusefilter group.
Leave the following permissions unassigned for now:
Set $wgAbuseFilterAvailableActions to array( 'flag', 'throttle', 'warn', 'disallow', 'blockautopromote' );
That is, the permissions 'block', 'degroup' and 'rangeblock' should be removed from this array.
The native parser (under parser_native) should be built (ask River for details),
$wgAbuseFilterParserClass should be set to 'AbuseFilterParserNative'.
The variables defined underneath should be assigned to the appropriate values depending on where this native parser is built:
$wgAbuseFilterNativeParser = "$dir/parser_native/af_parser";
$wgAbuseFilterNativeSyntaxCheck = "$dir/parser_native/syntax_check";
$wgAbuseFilterNativeExpressionEvaluator = "$dir/parser_native/af_expr";