Assuming half of it is bandwidth costs, that means that a daily active user is using ~380 MB/day (assuming $0.01/GB). That seems pretty hefty as an average. Especially if you consider the encoding snapchat uses puts each 10s video at about 1MB in size. 380MB is a little over an hour of snapchat quality video, that seems excessive as an average. If I were a major stockholder I'd be pushing to see why these hosting costs were so high.

I bet bandwidth is a large cost, but I bet compute is a big component too. Snapchat uses Google App Engine, an awesome platform but expensive (comparable to Heroku).

Regardless, my understanding is that Snap now gets some sort of flat rate deal from Google, so not sure how important the individual components are.