[jimaek]

Grouped URLs are cached as always but for less time. You can check the headers.

[eli]

I think the parent's point is that people will less likely to have a warm cache because it's less likely any other site has requested the exact same group of files.

(Though there's debate as to how much that matters.)

[jimaek]

Personally I think they only file that is going to be already cached is jQuery from Google. So for the rest it doesn't matter. Just my opinion.