PaaS (Platform as a Service): It seems like you can put any service in the cloud these days and slap “aaS” on the end to make it a ‘thing’. Platform as a Service is there for developers who are developing or customising applications. It’s got its own operating system, database, and web server, and it’s a quick and economical way of taking web apps from the bright idea stage to up and running. Scaling is easy because it’s in the cloud, and PaaS names you’ve probably heard of include Windows Azure and Google App Engine.
Please note that technologies described on Wiki pages are not necessary the part of Plesk control panel or its extensions.