A couple of hours later my friend gets an ad titled: "Unique Business cards by MOO"
screenshot: http://imgur.com/MPa3YZv
I might be paranoid, but Facebook is creepy like that.
Food for thought: when Uber first announced API integration w/ FB Msgr, I was interrupted several times w/ Uber requests in-convo when talking to a friend about restaurant recommendations in London.
*EDIT: ...while both of us were still in the U.S. Too bad I didn't screen cap; I thought it was hilarious at the time.
I only use messenger.com to chat and sometimes I go to facebook.com to read the wall.
All my ads are either based of sites ive visited or context of my chats.
For example, if you are talking about cheap plane tickets to Hawaii, it is in their best interests to show you those things based on the ads. I don't think Facebook is going through the billions of accounts and the millions of conversations that go on everyday. That is a lot of manpower and despite the billions of dollars that Facebook and Google make, its not worth it to them. The CIA or FBI? Sure.. perhaps, but hate to say it: most people are boring. They care about people talking about terrorist activities. So they may measure for those words and might look more closely at the account.
From my own account of developing similar tools, such as a web creation platform, I created a section that allows me to monitor posts. There is a fine line between being in people's business and monitoring it just to ensure that no one is breaking the rules. I don't personally read the messages and I don't use the information for anything. Rather, I have to keep an eye on the "general" because people (hackers?) have learned to use some my web apps for their own purposes of distributing malware, viruses, etc. And while I don't care if they post pornographic material, I do monitor to ensure they aren't posting about violence or encouraging it.
It goes with any website: They are there to protect their own best interests and create a good experience for ALL USERS. Since I give my web app users free reign to share links, write whatever they want, and it is free, they have to give me, in return, the ability to at least make sure the website is safe. Imagine being a website known for distributing malware and other things: your ranking will drop, and all of the people who enjoy using your web app suffer. This is somewhat the price of "free": giving those who created it access to profit from your account or monitor your account within reason.
I will search Amazon for a bunch of stuff and I might not find it. I log into Facebook and they are showing me ads from Amazon. I have no doubt that Google, Facebook, and Amazon all have tools working in the background to scan through your "temporary cookies folders" and looking for things that match its own database to try and sell you the things you were looking for.
I work for a media marketing company and many times, Google, Amazon and Facebook are showing me ads that are closely related to what I have been working on -- despite the fact that the information I am working on has not even gone public yet. For example, lets say I'm designing something for NABISCO Oreo cookies. An HTML landing page or whatever the case may be. The software I'm using probably sets cookies that store some information. When I navigate to Facebook, it is showing me ads with Oreo cookies. How would they know this information? This leads me to believe that they do, in fact, have software scanning through your cookies -- not to steal information per se, but to show you ads and make money on you.