A captcha system that uses successful decodings to helps digitise books for online use. Background, and details on how to incorporate into a site. Source code in several languages, and plugins for popular blogging and CMS software.
Snapshot of Recaptcha.net| Rank | |
|---|---|
| Senate.gov | 830 |
| Lego.com | 831 |
| Softonic.com | 832 |
| Domaintools.com | 833 |
| Recaptcha.net | 835 |
| Io9.com | 836 |
| Trails.com | 836 |
| Makeuseof.com | 837 |
| Proboards.com | 837 |