At any on our sites we will have for sure a form, either for requesting info, for suscrbing to newsletters, to buy in our store, or just to sign up, ..and there are some people out there who enjoy behave a little bad either to shutsown your server, to fill your database or just to spam those forms. The solution as you all know is to install a Captcha, "put a nice car in you live and a nice captcha in your forms".
What is a Captcha??, I assume most of you know but at any case it means: "completely automated public Turing test to tell computers and humans apart." What it means is, a program that can tell humans from machines using some type of generated test. A test most people can easily pass but a computer program cannot. Have you see them??
There are many out there but the one I prefer is recaptcha. It has the next functionality as stated in its site:
- It's Free! Yep, reCAPTCHA is free.
- It's Useful. Why waste the effort of your users? reCAPTCHA helps to digitize books.
- It's Accessible. reCAPTCHA has an audio test that allows blind people to freely navigate your site.
- It's Secure. Most other CAPTCHA implementations can be easily broken.
- It's Popular. Over 100,000 sites use reCAPTCHA, including household names like Facebook, Ticketmaster, and Craigslist.
- It's Easy. reCAPTCHA is a Web service. As such, adopting it is as simple as adding a few lines of code on your site. For many applications and programming languages such as Wordpress and PHP we also have easy-to-install plugins available. We generate and check the distorted images, so you don't need to run costly image generation programs.