http://www.pineight.com/rant/captcha/

Commons is listed under "confusing examples":

Wikimedia Commons links to Special:Captcha which mentions (but does
not obviously link to) Commons:Contact us which links to Commons:Help
desk, which permits anonymous posting. (Some other Wikimedia sites,
such as English language Wiktionary, use the same CAPTCHA. The English
language Wikipedia does not use a CAPTCHA at all.)

Presumably they're referring to signing up for a new account. (I think
captchas are also triggered when anon users introduce new external
links.)

Can anyone confirm or deny that enwp doesn't have the same captcha?? I
thought all WMF projects had the same one now?

When creating an account on the English Wikipedia ( http://en.wikipedia.org/w/index.php?title=Special:Userlogin&type=signup) it has a captcha as well, but the text reads the following:

"To help protect against automated account creation, please enter the words that appear below in the box (more info):

Unable to see the image? An administrator can create an account for you."

(in case links don't show up, they are http://en.wikipedia.org/wiki/Special:Captcha/help for "more info" and http://en.wikipedia.org/wiki/Wikipedia:Request_an_account for "create an account for you")

Just a more specific page to go to if you want an admin to create your account, instead of asking people to request assistance at the help desk. I haven't checked other wikis, can't speak for them...

--
Ayelie
(Editor at Large)