I'm sure I'm not the only one who's had this happens. But I have had 3 providers in AZ pop up on my FB people you may know. The first time I the page and we had quite a few "mutual" friends although with FB that doesn't mean much.  

Obviously I would never reach out via FB for a number of reasons.  

Just curious  if this is common. I figure the ladies I did see weren't as diligent about their privacy.

This started happening to me several years ago.  At first it was their professional accounts, then their personal accounts showed up.  Every time their personal account showed up, I let them know about it.  You can't beat the algorithms; they will out you every time.  The only way to minimize it is to use Tor and an encrypted email client.

but (a) I am a low-volume guy and (b) I don't use Facebook much and have a fairly restricted circle of friends. Personally, I'd be a little freaked out if I started seeing that; I'm kind of paranoid about online privacy anyway.

 
I'm not sure how that would happen. For one thing, you're probably right about the ladies not being real diligent about privacy. Social media seem to be really sneaky about tying together spheres of life that we might rather keep separate. I distrust them by default for that reason.

You know a lot of girls screen by googling the internet.  Once facebook sees them searching for you, it'll remember and offer you the opportunity to friend them.  Facebook wants you to connect with everybody.  It works hard to make that happen.

Search that subject line, "Social Media: Avoid Like the Plague That It Is" on General, Newbie, S&P, NY and Boston going back several years. You'll get lots of threads and discussions of near or actual disasters that occurred when Real Life and Hobby Life crossed unintentionally yet unavoidably.  
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Sit back, do nothing, and watch as the nefarious tentacles of SM start to ensnare and mix up friends and contacts from your separate worlds with Real You and Hobby You as the only common denominator.
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The stated purpose of  FB, Google+, Twitter, Snapchat, .... is TO CONNECT EVERYONE ... WHETHER THEY WANT TO BE CONNECTED OR NOT!  They are very good at it. AVOID SM!

I know it's usually called "social media" but recall the backing of that social media platform is a social network.

 
You mentioned that you have friends, who are friends with these providers. Look no further, they are being recommended to you because Facebook thinks that you know them. If you didn't know that they were providers, you'd never know that they were showing up on your facebook.

 
Now, you might be assuming that Facebook has somehow hacked your phone/computer/brain/dog/etc, but this is exposure bias.  

 
IF you've saved these women as contacts in your phone AND you've used that number to setup your facebook profile AND you've installed the facebook app on that phone that has that number AND you've allowed facebook to sync your contacts THEN you've definitely networked yourself to said women and you are, for lack of a better term, totally fucked.

 

Granted, you're at fault here for having poor operational security, and facebook simply did what you (inadvertently) asked it to do.

I hear that. And I'm hoping they never cross more than they have.  

I actually was introduced to a young lady a couple years ago and come to find out in my hobby time I came across several ads of hers on BP and other escort sites.  I don't think she would remember me but the fear she might kept me from seeing her. Sucks because she is incredibly sexy and her reviews are what dreams are made of.

I had a crappy old flip phone. Then I got a smartphone and entered the numbers of the escorts I see most frequently. The next thing I knew, she showed up as a friend suggestion on fb, under her real name  to boot.

A better way is not to use your smartphone for P4P.

As we reach a stage of convergence, where all of your activities are online and cross-referenced by virtually every program/app/platform, we will see more and more of this.

Just another reason why I have NO social media presence (aside from LinkedIn) and everything is as separate as I can make it. No FB, Twitter, Instagram, none of it -- be as insular as you can be in your everyday life and keep the p4p world as separate as you can make it.

I recently just got rid of my personal social media accounts, but doesn't the "location" settings on your phone have something to do with this also? For example, if Facebook is using your location even in the "background", when you leave a place, people you saw there would show up; even if you didn't have their number? I would imagine if this is the case, it might be as simple as removing the location privileges from social media applications.

1.  Establish a totally separate persona that never touches the real you - burner phone, email (and client), ID and name.
2.  Never give any app access to your contact list.
3.  Never use anything established in #1 for anything related to your real life.
4.  Never use anything not established in #1 for anything related to the P4P world.