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It will be interesting to see who has the last word, but for the moment it appears that Wikipedia does. As of today, they have banned the Church of Scientology from editing any articles on Wikipedia. Thursday, the site’s arbitration council voted 10-) (with one abstention as reported by The Register) to ban any users that come from all IP addresses that are owned by the Church of Scientology and its associates.
They went even further, specifically naming editors that are now banned as well. These editors are banned for six months, until they can show that they can abide by Wikipedia’s rules.
Wikipedia explicitly warns that it does not allow people and companies to massage the information that appears on their powerful site. This specific case, which started in December, focuses on over 400 articles on Wikipedia that have been repeatedly edited by critics of Scientology and by Church of Scientology editors. This is actually the fourth arbitration case that Wikipedia has taken up with Scientology.
The Church of Scientology has not, as of yet, commented on the situation. But you can bet they will – or that their lawyers will.