Forum OpenACS Q&A: Re: Hello! New to AOLServer and OPENACS. Question...
there are plenty of docs laying around on the background and purpose of openacs. basically, it's a set of tools (database connectivity, templating, cacheing, on and on) that you'd use to build your own functionality (like the photo album) without having to start from scratch.
instead of picking code to use in your own system, you'd want to install the openacs core framework and either add packages on top or write your own packages. you'll find doing this makes things *much* easier as a lot of work will have already been done for you.
why wouldn't you want to run the whole thing? what kinds of things are you looking to do on aolserver outside of openacs?