eBay monitors and reads your messages

[SunTzu]

So I was spending one lazy evening perusing the abyss of watch listing on eBay when I spotted a watch I liked. I private messaged the seller and offered an amount to see if he would be willing to sell it to me. He agreed. He has 100% feedback and I PayPal'd him the money. It wasn't a lot of money. We communicated a little back and forth. Nice fella. He generated a shipping label and told me it would go in the mail the next day. I've done this on one or two occasions with other items and even developed a nice online business relationship where I would receive a contact before he listed items to see if I wanted to buy. Like getting first dibs and negotiating a mutually agreeable price.

Anyway, 2 weeks later, today, I get an e-mail from eBay, a warning about buying outside of eBay. Now I understand they lose out on a cut and I'm using their platform to buy an item they miss out on. I get that.

BUT, in this e-mail is the whole chain of communication I had with the seller! It was literally lifted and pasted into this e-mail to me, word for word. My "private" messages were monitored and I guess flagged for rules violations. I was let off with a warning.

I was left rather shocked that my messages were monitored. I didn't know this went on. I'm sure it's buried in the fine print we all read (sarcasm) and accept to use their services.

It's led me to wonder about e-mails or texts I use with Verizon, or Google, or Yahoo. Even Facebook messages for those that use (I don't). Are they also monitoring my (our) private messages? We are using their services like we use eBay. I know the NSA has the metadata, but companies filtering, monitoring, and reading them? If I'm sniffed out on eBay, what can I (we) be sniffed out for in other messaging platforms?