i'd have to disagree. a ton of the slowdown in modern sites is due to lack of front end optimization. optimizing CSS rules is probably a waste of time, but the other basics (outlined by Steve Souders) can make a huge difference. as he says, 80% of the time is spent on the front end.

a lot of web sites and apps that depend on the database are aware that this is the bottleneck and optimize for that without giving the front end much consideration.

go look at the waterfall chart for techcrunch.com and tell me where you think their problem is.