Your understanding (highest [Internet] traffic) seems correct, given that it is used on an e-commerce site.
But I want to point it out that it is not a standard/correct word. Chinese have a lot of freedom in coining new words but not all of them are fine ones. Of most IT-related idioms, 超 is translated from hyper, so we have 超链接(hyperlink), 超文本传输协议(HyperText Transfer Protocol), etc.
Nobody can give an exact meaning of 超流量平台 because it is not a standard IT idiom published by 全国科学技术名词审定委员会（China National Committee for Terms in Sciences and Technologies ）. That's why I said in my previous answer, it is just an ill-devised fancy word.