There is no optimal Captcha. All of them block the access for some human users, so Captcha can't make the distinction between humans and non-humans, but only the distinction between sighted humans and anything else.
reCaptcha offers an audio alternative for the blind but it is almost uninteligible almost always. And there are users which use a Braille display because they are both blind and deaf also... So, I would recommend using reCaptcha only if it is absolutely necessary, for example if you work for a site that will probably have very very many users, and if you think the spammers would make the effort to create a scraper specially designed for that site to create accounts and submit spam. Captcha is overkill if it is needed just to block the general spam robots that can work with all the sites. --Octavian ----- Original Message ----- From: <peterp...@bk.ru> To: "The elegant MVC web framework" <email@example.com> Sent: Friday, December 14, 2012 11:33 AM Subject: [Catalyst] The optimal captcha > Hi! > Needed the captcha for project. May some one recommend something about? > > _______________________________________________ > List: Catalyst@lists.scsys.co.uk > Listinfo: http://lists.scsys.co.uk/cgi-bin/mailman/listinfo/catalyst > Searchable archive: http://firstname.lastname@example.org/ > Dev site: http://dev.catalyst.perl.org/ _______________________________________________ List: Catalyst@lists.scsys.co.uk Listinfo: http://lists.scsys.co.uk/cgi-bin/mailman/listinfo/catalyst Searchable archive: http://email@example.com/ Dev site: http://dev.catalyst.perl.org/