Validating human users

Recaptcha is an interesting service for identifying human users that also provide the additional benefit of translating scanned text to digital form. Validating human users is highly relevant because bots run around the internet adding them selves to services. This is also a reason for using things like facebook or google accounts to identify new users, that they are already identified as users, so the need for every service to verify human users is not as mandatory as before but it is still a good component to add to your application when registering users.

Many alternatives exist of course but what is particularly interesting here is that Recaptcha also helps translate text while identifying users so it provides a dual service.