Many sites make use of codes which are sent to your mobile phone as an SMS to verify you to sign up for a service offered by them just like email verification system . The aim is very similar to CAPTCHA for determining real users and preventing the same user from having multiple accounts except it is ...

Back in 2012 I had published a list of 5 free tools to share and protect your email address which proved to be useful to a lot of people.  Eventually Internet has become a home to spam and millions of spam bots crawl the web continuously to find new email addresses and bombard them with spam mails thus ...