Owen Wilson in a Ninja Outfit's page

Magically imbued with sentience, these items think and feel the same way characters do and warrant being treated like NPCs... Intelligent items can actually be considered creatures because they have Intelligence, Wisdom, and Charisma scores and should be treated as constructs.

As you can see, intelligent items are indeed considered creatures, and are treated as constructs. This is true in Pathfinder, and was a precedent set at least as far back as 3rd Edition D&D with nearly identical statements. However, to my knowledge, these statements have never been elaborated on, even though they carry a series of nontrivial mechanical connotations.

I asked many questions about the rules in my first post, and I thought that would be fairly obvious. I attempted to frame my many questions in almost a short essay format, rather than just a series of bullet points, so as to hopefully stoke the curiosity of others and promote discussion. But I will present those questions more clearly here, for everyone's convenience, and to hopefully avoid further confusion.

• What does an intelligent item gain from being a creature?
  
• What does an intelligent item gain from being a construct?
  
• Intelligent creatures can take feats and class levels. Can intelligent items take feats or class levels?
  
• Are intelligent item powers treated as a creature's spell-like abilities (and therefore provoke attacks of opportunity), or as a magic item's abilities simply activating automatically (and therefore do not provoke attacks of opportunity)?
  
• When concentrating on a power, what conditions, if any, prompt a Concentration check from an intelligent item?

What is an intelligent item? It might seem obvious at first; it's just a permanent magic item with a few extra features and some personality. It's a trusty talking sword, or an evil ring with a will of its own, or a hungry Bag of Holding. But intelligent items are actually underwritten in a few important ways, a problem Pathfinder inherited from its predecessors years ago, and these gaps in the rules lead to serious questions about the complete function and nature of intelligent items.

Because they possess ability scores, intelligent items aren't just objects, they're creatures, and are treated as constructs... but for what purpose? Ordinary items already have Hit Points and Hardness. But if intelligent items are creatures, do they gain racial Hit Dice, a Base Attack Bonus, skill points? Do they gain any construct traits?

Intelligent items are also said to think and feel as characters do, and should be treated as NPCs. They aren't mindless creatures; unlike most constructs, they have an Intelligence score. Intelligent constructs, like any creature with a mind, can take feats and even class levels. But what about intelligent items? They are creatures with a mind, after all. Could an intelligent item also be a sorcerer?

Sorcery or not, intelligent items can have "powers": special spell-like abilities that only the item can use, as a standard action. A typical unintelligent permanent magic item may also have abilities that only its wielder can activate, usually as a standard action, and that do not provoke attacks of opportunity. But a creature using a spell-like ability does provoke attacks of opportunity. So, when an intelligent item uses a power, should that be treated as a creature using a spell-like ability, or as a magic item simply activating itself? When concentrating on a power, what conditions, if any, prompt a Concentration check? For example, does an intelligent sword have to make a Concentration check for "violent movement" every time its wielder swings and attacks with it?

Knowing in what regards an intelligent item is a creature, a construct, or just a magic item, is key to understanding how they are meant to operate. Intelligent items can serve as powerful companions or enemies in your game, and ambiguity can slow down your game, cause disagreements, and lead to further misunderstandings. Removing that ambiguity could save a lot of time and trouble.