"In pursuit of the design goal of simplicity, we deliberately chose to measure only download speed, measuring how fast data travels from server to consumer when

"In pursuit of the design goal of simplicity, we deliberately chose to measure only download speed, measuring how fast data travels from server to consumer when they are performing activities such as viewing web pages or streaming video. Downloads represent the majority of activity for most internet consumers." I'm willing to bet additional factors that went into that consideration were: - Netflix gets massive download traffic on the cheap due to their scale. Upload, not so much - This tool is a clever way of preventing providers from throttling Netflix servers without also throttling a (hopfully soon to be) popular speedtest. Uploading isn't something they need their primary customers to be able to do.