Apache is a free and open-source cross-platform web server software.
Google AdSense is a program run by Google through which website publishers serve advertisements that are targeted to the site content and audience.
HTTP Strict Transport Security (HSTS) informs browsers that the site should only be accessed using HTTPS.
HTML5 Media enables video and audio tags in all major browsers.
Mailchimp is a marketing automation platform and email marketing service.
PayPal is an online payments system that supports online money transfers and serves as an electronic alternative to traditional paper methods like checks and money orders.
Varnish is a reverse caching proxy.