http://arstechnica.com/information-technology/2013/03/youtube-buffering-or-slow-downloads-blame-the-speed-of-light/?utm_source=feedburner&utm_medium=feed&utm_campaign=Feed%3A+arstechnica%2Findex+%28Ars+Technica+-+All+content%29
I will add that another thing that presents to users like latency, but isn't, is the processing speed on your device.