I consider this incorrect as as far as I understand it, it's should only be used for it is. Possession is not shown with it's but its or is it?? I was breezing about the net today and saw this little gem on a house sales page: "Its’ concrete floors are covered with carpets" Very strange, I've never seen its like that before. Source: http://www.moolf.com/interesting/man-builds-underground-nuclear-bunker.html
Well, as in the case of many adverts, this is one is wrong, and you're correct to have spotted it. (Don't miss today's big sale of broccoli, turnip's and potato's....) Its—without the apostrophe—is the possessive form of that word.
I've read the article. It's just a typo on the author's part. They use "its" correctly in other instances.
And you think Estate Agents are a reliable source for advice on grammar? Edited to add: Damn, and I thought I'd been quick off the mark!
It's not just its, it's all possessive pronouns. For ill-defined reasons 'it' is more confusing as a possessive pronoun. No one thinks to put an apostrophe in his or hers. Some might hesitate putting one in theirs but less often than wanting to put one in its. Purdue Owl
I think it's because "its" and "it's" sound the same. "I'm" and "my", "she's" and "her", etc. all sound very different. Perhaps it doesn't help that "its" is a possessive, and usually there's an apostrophe in a possessive.
It gave me a warm feeling. "It" is the subject. I gave in to its warmth. "Its" is the possessive. I gave in to her warmth. "Her" is the possessive. The warmth was hers. "Hers" is the possessive, not quite clear about how it differs from "her", but it appears to be that there is no noun attached to it.