I've spent the past week optimising How a Car Works for speed (mobile is 55% of our traffic now).
The average uncached weight of an article is 1.1 MB, of which 70% is Google Adsense and Facebook (the only two 3rd party scripts I include). I can't trim it any further and it's very frustrating - suggestions welcome btw.
Almost the only suggestions that Google's Page Speed tool has left are to minify the scripts that Google and Facebook themselves are serving.
I use Adsense because it's easy, pays fine, and the ads seem reasonably relevant. But the weight of crap being downloaded is absurd and I hate the idea of wasting some Kenyan's precious data allowance on an irrelevant advert that might earn me $0.01.
In fact, I'm going to use geolocation to not include Adsense in countries where I earn nothing.