CaptchaMe is a free service that protects your website from spam and abuse. captchaMe uses an advanced risk analysis engine and adaptive challenges to keep automated software from engaging in abusive activities on your site. It does this while letting your valid users pass through with ease.
As a developer you can earn money through this plugin.
Visit www.captchame.com for more information and registration.
Earn through free captcha for mobile applications and your websites.
Using this service users can :
1. Earn some revenue through your product
2. Preventing Comment Spam in Blogs
3. Protecting Website Registration
4. Protecting Email Addresses From Scrapers
5. Online Polls
6. Preventing Dictionary Attacks
7. Search Engine Bots
8. Worms and Spam