Google App Engine - A powerful platform to build web and mobile apps that scale automatically.
Pivotal - Pivotal Software provides enterprise PaaS-based solutions.
Heroku - Agile deployment platform for Ruby, Node.js, Clojure, Java, Python, and Scala. Setup takes only minutes and deploys are instant through git. Leave tedious server maintenance to Heroku and focus on your code.
Healthy Servers - Making server monitoring easy
DigitalOcean - Simplifying cloud hosting. Deploy an SSD cloud server in 55 seconds.
Hyperping - Cheap uptime and performance monitoring with detailed reporting and flexible alerting