Acquia Cloud Platform is a Drupal-tuned application lifecycle management suite with an infrastructure to support Drupal deployment workflow processes.
Cloudflare is a web-infrastructure and website-security company, providing content-delivery-network services, DDoS mitigation, Internet security, and distributed domain-name-server services.
Drupal Multisite enables separate, independent sites to be served from a single codebase.
Drupal is a free and open-source web content management framework.
Varnish is a reverse caching proxy.