Put built-in CAPTCHA to Contact Form
1. Click button to go to order page
2. You will receive download link on the e-mail address you submitted
Use built-in CAPTCHA on Contact Form.By default you can use it on several forms, but not on Contact Form.Stop spammers.
It nicely integrates with Magento 1.7+ built-in CAPTCHA, so you don't even know it is an extension.