[Nyubis]

^ This is the way to go. Don't waste any energy on the "unknown" word, just fill out the one that has been smeared out and fill in bogus for the rest.

If you want to post on 4chan and don't have a Pass, you need to solve a captcha for every single post. It becomes easier with practice, I fail maybe 1 in 10 captchas. And the more captchas you solve correctly, the easier the captchas for your IP get.

[ademarre]

If enough people colluded to use the same unknown word, say "foobar", then couldn't they train recaptcha to believe that is the true value of the word? If I understand recaptcha correctly, and assuming they don't detect collusion well, then eventually the known word pool would get poisoned with a surplus of foobars.

[_ofdw]

Some 4channers tried that already. You can guess which 6-letter epithet for black people they tried to use.

[Ntrails]

Ladies and gentlemen, I give you: "the internet".

[hueving]

>You can guess which 6-letter epithet for black people they tried to use.

'Blacks'

[nyrina]

Hint: It starts with "N" and ends in "igger"

[wernercd]

Naggers!

[mreiland]

did it have any letters in between?

[Rylinks]

An engineer said they have defenses against this

>Checking for offensive words is only one of the filters we have. Even without that filter, it’s essentially impossible to get recaptcha to return a false result.

http://musicmachinery.com/2009/04/27/moot-wins-time-inc-lose...

[shadowfox]

> it’s essentially impossible to get recaptcha to return a false result.

Famous last words :P

[viraptor]

This has happened in google image labeler. Now offline, it was a game where two random people were matched and needed to find new tags for the same image - the scoring was cooperative so points were given when you both chose the same word in the same game. /b/ of course quickly organised the jesusporn metagame... Label the first image as jesus, second as porn, third with jesus, etc. This resulted highest scores for some time.

[sesqu]

ReCaptcha does do some collusion detection, and I assume they do it well, since it has not publicly been stated to be a problem area.