SEOMoz's Search Engine Ranking Factors 2009
seomoz.org
seomoz.org
That being said, I think that having great (or at least good) content is a part of what leads to increased engagement with the blogosphere. I don't think it's necessarily easy to separate the two cleanly. Not that there aren't other aspects to blogosphere interaction as well, of course.
Back on topic: "cloaking" typically refers to hiding sketchy links, not hiding content or charging for it as Expert Sex Change does.
In my book, this is very similar to what Expert Sex Change does. Come referred by Google you get a nice answer at the bottom, come "clean" and you've got to pay for the answer. Very evil.
If you are a big guy (one infamous case was BMW Germany) you can do it, get caught and then recover from Google ban within a week. If you are a small site and get caught don't expect to do so.
I had some friends who would send googlebot to a clean, keyword-optimized piece of content, but the user would get sent to a page plastered in porn ads and would cookie stuff the crap out of their system.