Following on Mayer's comment about speed, a number of bloggers have been posting their thought about it. Here is one.

This person is obviously a speed freak. I like speed too, but I am ready to trade speed.

I can see at least a couple reasons.

Speed versus quality : I have posted about that earlier. Speed is nice, but quality is better. If Google for instance takes twice the time but comes up with the top 3 results I need, then I am ready to wait for it. I don't care if Google can come up at light speed with 10 worthless results (accompanied by sponsored links).

Speed versus reliability. If response time is low, but it requires constant interaction, how much the computer is helping me? When was the last time you started a washing machine and it let you down in the middle? Never. By sharp contrast, when was the last time you used a computer program, a web application in particular, that does NOT require you to be actively watching the screen, possibly interacting with dialogs or quirks? Yes, computer programs are absolutely unreliable in the sense it is only exceptional when you can start a task and not worry about how well it's going. That is obvious for customer programs requiring interaction in the first place, even though one may argue that because it needs some interaction at some point does not imply a constant interaction requirement (side effect, the user staring at the screen all the time. Advertisers like that though). An example : logging in Gmail using a slow connection.

Ajax/rich interaction. I think it's hard to justify Ajax when small Html can do just as well. If my background did not include Html, then I would perhaps swallow that "Ajax optimizes bandwidth, cures cancer and so on". Unfortunately, I am not ready to take that crappy argument. What works for me in web apps : simple, tiny, html. Period.

Broadband ubiquity : ah yeah. I think it will be long before this statement holds true. In the mean time, those writing web apps must test under slow connections if they care about their audience/customers. Unless they intentionally don't want them in the first place, which brings us to digital divide, web elite, ...