Spamty - Spamty is a web service to encrypt an email address and share it on the internet.
reCAPTCHA - reCAPTCHA is a free security service that protects your websites from spam and abuse.
Humans Not Invited - CAPTCHA that filters out humans and only lets programs pass
Hotmark - Create honeypots & protect your e-mail lists
hCaptcha - Do you use a captcha to keep out bots? hCaptcha is a drop-in replacement for reCAPTCHA that earns website owners money and helps companies get their data labeled.
Just For Fun - Showcasing creative side projects