The ability to embed google documents is very simple, but not intuitively obvious as it requires one to publish their google document first. This is a really great way to post pages of information with a lot of editing freedom without the limitations of bb code. Once a document is embedded in a post you can scroll through it and interact with it, but any edits to the document will need to be done via the google document itself.
The published page is automatically updated/re-published every 5 minutes or so (on googles end). This means edits made to the document won't immediately show up on the site, but will after a few minutes. Note that if you want to get rid of the excess white space around the text in your document, you will need to go into file > page setup and set the margins all to zero and the page layout to landscape. You can also edit the document background color in the same location.