I took a quick look, and I don't see anything that stands out. Assets are mostly cached properly, nothing is excessively large, gzip is on, etc. You've been getting a bit over 4 requests per second for the past three hours, plus some more before that, so roughly 50k views. 1 GB of data transfer means each view is averaging 20k. That still seems a bit higher than it should, but it's low enough that I'd worry about other things way before you start optimizing the bandwidth.