Here is my latest observation,
Now more and more web sites are exhibiting a new behavior.
Lets say you open a web page and read it for five minutes,
to read the page you downloaded 9 megabytes of data
and uploaded 4.5 megabytes of data.
A year ago it was rare but now it happens all over the web.
What is being uploaded? It use to be a much smaller upload
talking to the site.
Part of it is ad behavior but it happens to an extent
even if you block the ads on some sites.