Among the recent batch of spammers (and the one vandal I've encountered) it seems to become increasingly popular to target sites that only allow members to edit pages - which makes it more difficult for others who follow on the trail of the spammers to reverse the spam, if the site owners don't take action.
Some such sites have "join" buttons or simple secret passwords that are mentioned on the same page - but other affected have truly secret passwords or a manual application process. And if the spammers get into those sites, I worry that they have figured out some kind of exploit in Wikidot.com that allows them to become members while circumventing this process…
The Spambot Death Wall
Arcana Wiki - Distilling the Real World for Gaming
Urbis - A World of Cities - an urban fantasy setting of industrial magic
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