download, compilation, installation, and configuration took about a half day for me to have one instance of openacs running separate, customized websites handling multiple domains with user registration and management, news, forums, and file management... even a cheap chat module i wrote in about 15 minutes afterwards.
if you haven't by now, i'd advise actually trying to download and install on a test server. you'd be surprised how much functionality exists by default, much more than most web application packages i've seen and obviously more than hello world.
in the time it took you to write that question, you probably could have been well on your way to installing your own test site.
