There's another way as well; specify a range of time within which you expect the task to be completed. This also communicates your uncertainty about the estimate at the same time.
286 karma · joined December 22, 2010
@5l on twitter, aclloyds on github and bitbucket
Edit: obviously you could just avoid using this phrase on your site instead.
Of course your 'game' is hurting reCaptcha's goal of digitizing books.
[0] https://chrome.google.com/webstore/detail/jbhkdhkngalchoobjf...
It's possible to make a building like a skyscraper fairly earthquake proof, but is it really possible to make things like nuclear power stations earthquake proof? Assuming the building is made to 'wobble', wouldn't that wreak havoc on the cooling systems and other gear inside?