startup - 6:39 am on Feb 3, 2003 (gmt 0)
They are all forms of cloaking webwhiz. What is and isn't acceptable will vary from one SE to another. Where exactly is the line that if you cross over will get your sites removed. There is no one single answer to that question. Can a large company employ forms of cloaking that will get your site removed if you did the same? Yes they can. The playing field is not even, many times it(what is and not acceptable) is related to the size of your advertising budget and this doesn't apply only to cloaking.
I have come to view the public relations departments of all the SEs as "spam departments" or spin departments.