When you think about it, it wouldn't make much sense if canon occlumency didn't, otherwise Snape could never have gotten away with pretending to be a loyal servant of Voldemort. If he was obviously putting up barriers to keep his mind from being read, Voldemort could just have told him to take them down.
From the Wikia:
More advanced Occlumency involves suppressing only the thoughts, emotions, and memories that would contradict whatever it is an Occlumens wishes a Legilimens to believe;
I think that this would be enough. Snape only had to hide a few key conversations and actions from Voldemort; most of what he said and did in the Order can be open.
If Snape had been a good Obfuscumens, he could have fed Voldemort positive misinformation, but he didn't. He only kept secrets.
Update: Discussion has moved on to a new thread.
After 61 chapters of Harry Potter and the Methods of Rationality and 5 discussion threads with over 500 comments each, HPMOR discussion has graduated from the main page and moved into the Less Wrong discussion section (which seems like a more appropriate location). You can post all of your insights, speculation, and, well, discussion about Eliezer Yudkowsky's Harry Potter fanfic here.
Previous threads are available under the harry_potter tag on the main page (or: one, two, three, four, five); this and future threads will be found under the discussion section tag (since there is a separate tag system for the discussion section). See also the author page for (almost) all things HPMOR, and AdeleneDawner's Author's Notes archive for one thing that the author page is missing.
As a reminder, it's useful to indicate at the start of your comment which chapter you are commenting on. Time passes but your comment stays the same.
Spoiler Warning: this thread is full of spoilers. With few exceptions, spoilers for MOR and canon are fair game to post, without warning or rot13. More specifically: