[Catalyst] The optimal captcha

Derek Wueppelmann dwueppel at gmail.com
Mon Dec 17 13:47:22 GMT 2012

On 12-12-17 1:19 AM, Octavian Rasnita wrote:
> 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.
Just to expand on this a little bit. Of several text based Captcha 
systems Google's and Recaptcha are the only ones that I know of that a 
known exploit is not known. Google's has a better success rate than 
recaptcha but in both cases you are going to get a number of users that 
need to fill out the captcha more than once. If you need to allow access 
to people who have some visual impairment then using an audio captcha 
may seem like a good idea until you realize that they are really hard to 
solve sometimes less that half of attempts can succeed.
> Captcha is overkill if it is needed just to block the general spam robots that can work with all the sites.
This is true, if you just want to stop general spam robots you can take 
other actions to do so provide a form field that must be left blank is a 
very simple way to reduce the amount of spam provided by most spam bots. 
There are others as well. Using a Captcha does provide some advantages 
but it can also turn people away from actually using the system.

  o)   Derek Wueppelmann           (o
(D .   dwueppel at gmail.com          D).
((`     http://www.monkeynet.ca   ( ) `

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