Don't know about mobile, but I don't see ads on page. I close browser before, go directly to kid's page, read and comment there, revoke permissions and close browser.
Pale Moon set to dump everything on exit. One advantage to PC is NoScript. FB keeps telling me to use mobile site for full enjoyment of site. I just enable JS, then turn it off. Think that JS might be the biggest problem on mobile. Too hard to turn off.
Some browsers on the PC have extensions that allow you to turn off JS on the fly.
Android browsers need that extension instead of just JS on or off.
Most of the discussion with kid is about cats or ferrets. Not too much marketing for Weezes.
I am seriously waiting to find out whether the chance of selling something outweighs selected usage which means adding all your info so they can market. Chance of marketing would be more like the pesty telemarketers. Blanket everything to collect one nibble.
Yahoo has already admitted it will not abide by "Do Not Track"