Therefore, any attempt to spam any wiki or blog should be rewarded by bit-slapping the PageRank of the intended beneficiaries down to zero. Going further, repeat offenders could find entire clusters of sites slapped out of the top Google spots, with a long period of good behaviour required before the site is reenabled.
If Google were on good terms with other search engines, they could pool their resources and provide a unified front against malicious SEOs. Webmasters will be unlikely to pay for activities that effectively remove their site from the Internet's search engines.
But, aggravated spammers may attempt to subvert the system and cause chaos: instead of promoting their own pages, they spam wikis and blogs with links to their competitors, which then get bitslapped. The best approach, therefore, is to be entirely unpredictable in applying the bitslap. Take a few weeks building up a list, then bitslap it all at once. Wait a few months to prevent subversion, then repeat.
It is also very important to document evidence supporting bitslap decisions, such as snapshots of spammed pages and malicious half-way sites (used to improve the PageRank). Sites must be able to apply for a bitslap to be reversed once they have leashed their spam-hounds, and this evidence will help appraise whether a revert request should be honored. One could even email sites that have been slapped providing said evidence and clearly documenting the reversion process to bring home the message.
WikiSpam will not be solved until the motivation for spamming has been removed.
I suspect that they could hire one of the chongqed.org folk to do the footwork. The bitslap approach, being safest when sporadic, is well-adapted to freelance implementation. Cheap at twice the price ;) -- ChrisPurcell