It's amazing how many misunderstandings that can happen when you have to limit your message within 140 characters.
For one, all in for sprite sheets. Hell, if you take a look at the front page of this blog and take a closer look at the "Read More" buttons, you'll see that they are in sprite sheets.
They are essentially just two-image sprites, and done by me over a year ago when I was assigned to create a blog for NinjaForge. Yes, that's what you are looking at right now. And I did those long before I started learning about how HTTP requests affect loading times on your site.
You can read more on that yourself here.
Our latest works, Ninjaboard, I even made all the action buttons one big sprite.
What I meant when I said
IMO putting all your JS, no matter what the JS actually does, to the bottom, are as silly as putting all your images in a sprite sheet. on twitter, was not that you shouldn't be using sprites at all. What I said was you wouldn't put every single image on your site in a sprite sheet, but every single image that makes sense to put in a sprite sheet in a sprite sheet.
I don't have to tell you that constantly updating one sprite sheet one a site that allow users to upload their own images, would be a nightmare.
The reason I made that tweet in the first place was to prove a point I made to a friend on twitter. I made that exaggeration to illustrate other situations where follow a general rule, where it's sensible to do so.
In 90% of the cases, if each case is a fairly modern site that keeps up with the industry standards, putting all your JS at the bottom is the right thing to do.
Why is this a problem? If you worry about users that leave if the site spend more than 5 seconds to load, the very same group of people wont stay on your site if things don't work as they expect.
At best they'll simply think something went wrong while loading and hit refresh to try again. At worst they'll simple leave.
And no matter if they refresh or leave, then what's the point in causing that to happen, for the small benefit of a slightly faster loading site?
We are talking about marginal differences here, but as we move closer and closer to the world of applications rather than just pages, these things matter more.
These are my personal thoughts on it, hopefully this clear up any misunderstandings