A: 

as far as i know, yes - pretty much you "can always send raw DEFLATE and everything would be okay"... there is not "always", but most of all cases. if not, this is the browser's problem.

Itay
I'm trying to find the cases when raw deflate fails. According to spec it should fail in all browsers.
David Murdoch
+4  A: 

The Android 1.6 browser (v4) fails both the zlib and the deflate test on your page. I've added it to your list.

Josef
Thanks! What Content-Encoding does Android's browser send?
David Murdoch
It sends 'Accept-Encoding: gzip'.
Josef
Thanks again, I've updated your update. :-)
David Murdoch
A: 

Isn't it the case that AddOutputFilterByType DEFLATE using mod_deflate sends by gzip by default?

Paul Irish
Hey Paul, I feel like I'm talking to a celebrity...you are everywhere. :-) Anyway, `AddOutputFilertByType DEFLATE` gzips the response instead of deflating it by default (as far as I know). `Gzip` is `deflate` + a 10 byte header + 8 byte footer - which means that `Gzip` will ALWAYS be larger than `deflate`...so why should we ever use gzip? (see http://en.wikipedia.org/wiki/Gzip#File_format for a breakdown of what gzip is made of).With that said, I'm not sure how to go about setting `deflate` as the preferred compression method in Apache.
David Murdoch
Ah. thanks for the detail on that, my man.
Paul Irish