admin Yellowikis wrote:
I stumbled across this way to reduce comment spam:
http://www.gadgetopia.com/2005/03/08/PreventingSpamByKeystrokeCounting.html
http://overstated.net/projects/mt-keystrokes/
It's not perfect of course - but might be worth investigating.
It's a neat idea, but there are several serious problems with it, particularly so for a wiki environment.
Most seriously, it requires client cooperation -- a spambot can simply send the expected number of bytes along with the request. It can only therefore be effective against humans doing manual cut-n-paste of spam text... or real genuine humans cutting and pasting text.
It requires JavaScript, so either it cuts out submissions from humans with JavaScript disabled or unavailable or it must accept submissions without the number, making it trivially defeatable by humans...
For wikis, we send out the entire current page text and take back the entire text with modifications. Determining number of changed characters is not trivial; think again of cut-n-paste, rearrangement of sections, deletion of sections, etc. This makes it much harder to get meaningful information out of such a comparison.
-- brion vibber (brion @ pobox.com)