Alexa Certified Site Metrics is an analytics service wich monitors and analyses web traffic and can be used to keep track of user behavior.
Apache is a free and open-source cross-platform web server software.
Authorize.net is a secure online payment gateway service that enables businesses to accept payments through various channels, such as ecommerce websites, mobile devices, and retail stores, providing a trusted platform for processing credit card and electronic cheque payments.
Google Analytics is a free web analytics service that tracks and reports website traffic.