I admire the work done by those who have dug up such an incredible amount of examples in which "its" is used as a possessive pronoun.
However, as I'm not a native speaker of English, I normally go by the teachings of grammar books, so I looked up Swan's "Practical English Usage - Third Edition" which states :
Its is not normally used without a following noun.
I've had my breakfast, and the dog's had its breakfast too.* [NOT ... and the dog's had its.] 1
Another frequently used grammar textbook for EFL teaching is Murphy's "English Grammar in Use". On this subject the author does not go so far as to say that "its" is not used, still he does not list it along with possessive pronouns, which in my opinion is meaningful. 2
There are other grammars which share this position, on top of the indication to be found in OED, so I think it should be safe to conclude that, although the usage of "its" as a possessive pronoun is sometimes found in texts, still it is rather rare. And I would go so far as to recommend foreigners like myself to avoid using it whenever possible.
1 M. Swan "Practical English Usage" - paragraph 442 - possessives (4) pages 417-18
2 R. Murphy "English Grammar in Use" 2nd edition - Unit 81A page 162
(another reference could be Michael Vince's "Micmillan English Grammar in Context" which, when listing possessive pronouns, leaves a blank where its should be found.)