Apache is a free and open-source cross-platform web server software.
CentOS is a Linux distribution that provides a free, community-supported computing platform functionally compatible with its upstream source, Red Hat Enterprise Linux (RHEL).
DoubleClick Ad Exchange is a real-time marketplace to buy and sell display advertising space.
Google AdSense is a program run by Google through which website publishers serve advertisements that are targeted to the site content and audience.
Klaviyo is an email marketing platform for online businesses.
Quantcast Measure is an audience insights and analytics tool.
reCAPTCHA is a free service from Google that helps protect websites from spam and abuse.