Not even a comparison such as 400 gigs of bandwidth is equivalent to a company of X size/ brand recognition and would be operated by Y number of employees.
I can't give you corporate website figures, so this isn't quite what you're looking for. However, I can give you a very rough eqivalent - where I work we're using a little under 100 Gb per working day, roughly 2Tb per month. Scaling this, PPRuNe would be like an IT research company with around 200 employees. The bandwith/employee is higher than average and the pattern of bandwidth usage is all different, but it's a ballpark figure.