ReCAPTCHA A very useful and smart alternative to the traditional CAPTCHA. Very very easy to set up.
Ajaxload It’s not a ‘web service’ but a service for the Web, 2.0. Create your custom loading image to display during AJAX requests.
AddThis The number 1 bookmarking and sharing button. It gathers a lot of links. Very useful.
Ip2location Map the IP to the country.
