[lesuorac]

It seems fairly trackable though? Like money spend per second of loading time?

You do run into a weird problem where as the site gets faster for the p99 the median speed can get worse as people that originally avoiding the site over speed start to use it more often so you get a worse p99 population than before and the old-p99 creeps down into p50. But also you have more users so that's nice.

[graemep]

You have more users, hopefully more revenue, and a problem that can be solved by throwing connectivity and hardware at it - and you have already probably reduced your spend on one or both in making the site faster.