Do any other CMS have an equivalent of Drupal's Domain Access module?
It is a module which enables content from a single-site to be placed under different domain names, with reading and writing permissions all controlled by the user permissions system.
There is something else I have to add - Domain Access runs on the same database and the same table name prefix and the same directory. The different domains don't run on different sub-directories and databases and table prefixes
The Domain Access project is a suite of modules that provide tools for running a group of affiliated sites from one Drupal installation and a single shared database. The module allows you to share users, content, and configurations across a group of sites such as:
example.com one.example.com two.example.com my.example.com thisexample.com <-- can use any domain string example.com:3000 <-- treats non-standard ports as unique
By default, these sites share all tables in your Drupal installation.