As Glyn Wintle is fond of saying: if your security depends on a blacklist, you’ve already lost. Thusly, Cryptome reports:

Access to documents containing the word “WikiLeaks” are blocked at the US National Archives website.

http://research.archives.gov/search?v%3Aproject=opa&query=WikiLeaks

The URL you requested has been blocked
The page you have requested has been blocked, because the URL is banned.
URL = research.archives.gov/search?v%3Aproject=opa&query=WikiLeaks

However documents with the words “Wiki” and “Leak,” separated by a space, are not. Six documents with “Wiki” and “Leak” may be retrieved:

HOWEVER: it’s possible to do better than that! Whatever is filtering the search engine is not as smart as the search engine, because the search engine accepts wildcards.

Hence:

This is why censorship is a bitch to do, and why it’s an expensive road to take.

Dear everyone, you have two options:

1. avoid censorship, or else
2. work out and enumerate all the documents that you’ll allow people to see, so that you can whitelist them

Pick whichever option is cheapest.