What does it really mean when a post is "sponsored"?

Hi guys, here's a small departure from my usual parade of reviews but I wanted to take the time to explore sponsorship in the blogging world and what it means to me personally so you are all clear when I say "this is a sponsored post."  

I haven't been blogging for very long but I have been super fortunate to get free items from a couple different brands, most notably Grana.  And when they do give me free items, of course they never say how they want to review the go.  They never explicitly say they want a positive review and of course I try my best to always give my honest opinions no matter what.  But there's always probably going to be a little bias (I mean the fact that it was given free to you can't help but sweeten the deal).  But honest reviews are in my best interest so I would never compromise that.  And that's probably true for most bloggers out there.  But I do feel it should be stated when an item was received for free by a company then it technically becomes a "sponsored" post.  At least in my book, free= sponsored.  But sponsored never just means a favorable review (case in point, Grana's silk sleeveless blazer and silk joggers).

And for the most part I'm able to write positive reviews on the handful of sponsored posts I've done because I've partnered with brands that I've already had experience with (i.e. I already purchased their items with my own money, wrote up a review, and then they found me).  Well why do I bring all of this up now?  Because I'm heading into uncharted territory by working with brands that I haven't tried out before.  But I'm committed to give honest opinions even if it means a negative review (actually I got really lucky and I ended up liking the product, but I realize I might not always be so lucky).  And well if it leads to zero free stuff in my future I'm okay with that too (plus to be completely honest I rely more on the referral links for store credit for most of my reviews, so really I need you guys more than the companies themselves offering free stuff).

Anyway for other bloggers' take on what it means to get "sponsored," "gifted goods," or something "c/o" read here and here.