"Facebook does not use your phone's microphone for ads or News Feed stories." http://newsroom.fb.com/news/h/facebook-does-not-use-your-pho... The phenomenon you're observing is due to various interesting human psychological quirks, such as priming effects. https://en.wikipedia.org/wiki/Priming_(psychology)
Frequency illusion or Baader-Meinhof Phenomenon is probably a better term to search for: http://rationalwiki.org/wiki/Frequency_illusion But I don't think it's chance here. I think the facebook app has location access and if so they are definitely using it (e.g., the place might be popular for campari, your mutual friend appearing at the same location might've searched/wrote about it, etc). For example google is pret…
I was once reading Fear and Loathing on the Campaign Trail '72 by Hunter S. Thompson (which I can heartily recommend) - not an especially obscure book, but certainly not his most famous. I was a student, and I was lying on my bed reading this book, whilst listening to some music. This was about 2000, and I guess I was a relatively early adopter of online streaming music: I'd selected some random electro music station to listen to. I'm reading my book and listening to some moderately uninteresting electro when a sample in the music piques my interest - I recognise the voice! It's Hunter S. Thompson. I think, "That's a funny coincidence, given what I'm reading..." Then I listen a bit harder and I realise he's talking about Nixon (or McGovern, I forget). I realise he's reading from the very book I'm reading - and yet, it seems even more familiar than that, like I've just read these very words... I glance down at my book and realise he is, in fact, reading the start of the very paragraph I'd just, seconds ago, finished.
I wasn't on drugs and I haven't embellished this story over the years, it really did happen just like this. Just a lot of chance, right?