[vorticalbox]

they will know that this IP sent this much data to that IP but not what was inside it.

Your ISP knows the same when using a web site via HTTPS. They can see you send a request to the website but not what it contained.

You could also use a VPn or TOR if you want to hide your IP.

[soziawa]

And they'll know who you contacted and when. That allows for a lot of things to be guessed. Especially with hundreds of thousands of messages per user available to them.

Yeah, but my ISP has to follow the local laws and I can easily switch ISPs if I dislike my current one. Try that with Facebook.

Yeah, I might use a VPN but I'd also have to force all my contacts to use one as well.