The researchers wanted to see if the number of positive, or negative, words in messages affected whether users then posted positive or negative content in their status updates.
The main conclusion was that emotional states can be transferred to others via emotional contagion, leading people to experience the same emotions without their awareness.
When the news broke, the websites and Facebook pages of several media outlets were asking people to get in touch if they were affected - or felt used - by the experiment.
I found that odd, as I wouldn't know what I was doing during an unspecified week in January 2012 and I definitely can't remember a thing about what I saw on Facebook during that time.
The study was legal according to Facebook's rules but questions are being asked about whether it was ethical.
According to the stories on a range of news websites, people were upset and outraged about it, and many had lost trust in social networks because of it.
I'm not worried at all if Facebook would pick me out and use my wall for a psychological experiment without my permission.
What a great platform it is to use for such an extensive study.
I find it clever and fascinating.
I don't really care if people can see photos that are posted on my page either, or, find out if I am single or not.
I do have security settings, of course, but everyone should be savvy enough to not post things online that aren't safe, sound and kosher.
If it is likely to come back and bite you on the bum later, don't post it.
What I enjoyed most about all this was reading the comments on the NZ Herald's Facebook page about the experiment.
Its initial post said there was outrage over the study, but most of the paper's followers who commented didn't seem to be upset about it at all.
Nicola Stanaway said: "If you think that anything you do online is safe and free from manipulation then you are seriously misguided.
"Also ... highlights the need to read terms and conditions haha."
I agree with Kevin J Hodges, who said that it is merely the electronic equivalent of placing sale items on one side of the store or the other, and observing where shoppers head to first.
He calls it no big deal and a non-story.
The thread was a great example of an interesting online debate and some people really cared about the secrecy.
Christopher Wood posted there are standards of ethics for science for a reason. And this experiment violated them.
"You should get informed consent from test subjects, especially if you're trying to manipulate their emotions (regardless of whether you succeed)," he said.
This was followed by a reply from Norman McIver who said: "That's funny, I've never been asked by TV media for consent for their ads which are structured around creating emotional intent."
That just hits the nail on the head because manipulation is all around us. It's a fact of life that our thoughts and actions get influenced all the time.
Advertising professionals make big bucks from it.
Everyone knows advertising is a form of marketing communication used to encourage, persuade, or manipulate an audience to take or continue to take some action and we all fall for it on a daily basis.
Those who are seriously worried about their privacy or manipulation should stay away from social networks and other mass media altogether but, of course, that's a little hard to do in this day and age.
Martine Rolls is a Tauranga writer and digital strategist - www.sweetorange.co.nz
