Not sure why this was censored from the article, but...
While MediaWiki is officially supported by the commercial CleanTalk.org service, the service was primarily designed for other purposes - such as blocking comment spam to Wordpress and similar blog software, blocking spam webforum posts and the like. A wiki differs from a forum or blog comment as the wiki user takes an entire existing section of an article (or an entire page), often modifies just a small portion, then resubmits the entire revised text as the "new" version of the page. If there's content that CleanTalk sees as questionable or spammy (such as external links or contact info) CleanTalk may add the user who edited the page to its semi-public IP blacklist or e-mail address blacklist, even if the offending content was in the original article before the user made the edit. This can cause false positives.
Cleantalk does provide a webpage where the administrator of a client site may see what's being accepted or blocked. This interface has a provision to manually report a result as a false-positive or false-negative. Unfortunately, reporting a result as a false positive will not get the unfortunate user removed from Cleantalk's "naughty list". Cleantalk does list more "bad" IPs than other comparable services - such as the (free) StopForumSpam - but it comes at a price of greater numbers of false positives.
The effects of a false-positive are also more severe on a wiki than on a blog-style comment form. If a blog comment is sidelined in error, there is usually some way to manually let it through. The same provision does not apply to failed attempts to edit a wiki page, and likely can't be easily provided if other users have been editing the same page in the meantime (leading to edit conflicts if the erroneously-blocked revision were manually resubmitted later).