Please take a moment to check out our new plugin, Confident CAPTCHA: http://wordpress.org/extend/plugins/wp-confident-captcha/. It's an alternative to those hard-to-read, annoying CAPTCHAs that show distorted and warped text. Confident CAPTCHA presents the user with a grid of photos and asks them to click on specific pictures to verify that they're human.
Because it's picture-based, there's an opportunity for it to become an advertising platform in the future. Bloggers and website owners could opt to include a couple sponsored images with the CAPTCHA image grid and earn revenue.
Please, check it out, try it on your sites, review it and vote for it. Thank you!