There was a tool which was used to trace forum leaks/mirrors, it was made/used by an Eve Online Alliance of all things. (If you can find a 2010/2011 mirror of the "Pandemic Legion" forums there should be a description of it on there).
From what I read it would introduce subtle changes based upon some identifier (either IP address, user account or both).
The variation was generated by using unicode characters which were either invisible or very close substitutions to actual characters. This could be countered by anyone who knew it was there however.
There was also the ability to write a block of the post in multiple different ways. With 5 blocks written 5 ways each you can get 3125 different variations of a post.
There is probably some interesting mathematics relating the level of redundancy to the minimum number of documents that would be required to make an un-tracable version.
From what I read it would introduce subtle changes based upon some identifier (either IP address, user account or both).
The variation was generated by using unicode characters which were either invisible or very close substitutions to actual characters. This could be countered by anyone who knew it was there however.
There was also the ability to write a block of the post in multiple different ways. With 5 blocks written 5 ways each you can get 3125 different variations of a post.
There is probably some interesting mathematics relating the level of redundancy to the minimum number of documents that would be required to make an un-tracable version.