AddThis is a social bookmarking service that can be integrated into a website with the use of a web widget.
Apache is a free and open-source cross-platform web server software.
Websites that have a shopping cart or checkout page, either using a known ecommerce platform or a custom solution.
Joomla is a free and open-source content management system for publishing web content.
PHP is a general-purpose scripting language used for web development.