I've said (only half-jokingly) Facebook is an intelligence gatherer for an invading army from space. We share everything about ourselves in social media, and marketing firms are using that data to target potential customers.

I recently reported Pandora Radio is using people's musical selections to project which way they may vote in impending elections.  Facebook can apparently tell when you're falling in love.

Business Insider reports, the interactions between Facebook users offer clear indications. Facebook Data Scientist Carlos Diuk says there's a very clear pattern, in which post are shared, interaction escalates, then levels off, but becomes more intimate.  If you've recently hooked up with someone via Facebook, don't be surprised if posts from florists, gift shops & restaurants start appearing on your timeline with  greater regularity.