Yeah, I feel Messenger or WhatsApp doesn't really come into play here. Facebook has at least two different privacy settings when it comes to phone numbers and how it's shown to people:
1. At https://www.facebook.com/USERNAME/about_contact_and_basic_in... - there's a contact info section where one can fill in a phone number (among other details) and set the visibility to Public/Friends/Friends except <group>/Only me/Custom/custom lists.
2. And https://www.facebook.com/settings?tab=privacy - there's a "How people can find and contact you" section that covers "Who can look you up using the phone number you provided?" with options of Everyone/Friends of Friends/Friends/Only me. I imagine it'd be very easy to select the wrong thing during setup due to the overwhelming number of things to read and click.
I suspect those who have set the latter, or both options to "Everyone" will most likely be in the "free" data dump (except perhaps for most Australian Facebook users, for now).
I feel the second setting is riskier, especially if you don't want employers or colleagues to be able to simply look you up on Facebook by phone number. For example, I could hypothetically display my phone number to "Everyone" on an incognito profile and no one should be able to just wander by and spot my profile and immediately figure out who I am (assuming this profile doesn't somehow get suggested to "Friends you might know" - big assumption, yes; but this would depend on how I complete my profile). Regardless, either one or both set to "Everyone" is a recipe for disaster.
I believe more people would have allowed number searching compared to those who just have their phones displayed to everyone on their contact info sections. In effect, it's a bit of a reverse phone book, plus extra.
I've lost around 20kg 2 years ago and were able to fit into a nice pair of slim jeans I used to wear in high school (around mid 00's). I've always carried my wallet in a left hand pocket and my phone+headphones in a right hand pocket. I couldn't fit any modern smartphone into the right hand pocket - the pocket was too short and your phone sticked out of the pocket all the time.
Kinda interesting, how the spread of modern computer devices changed a little detail in mass market fashion design.
You can search for your own topics of interest. If you want movie recommendations, it seems more sensible to browse through the site for movie buffs, not the one for engineers.
I posted here precisely because I wanted /your/ recommedations. There are some super smart people around here, and HN is my main source of thought-provoking articles.
There's also an entertaining movie based on this book, a rare business film that is more about failure than success.