Sorry to post this in the obviously wrong forum, but Battle.net and WoW have some close ties, and this has nothing to do with gaming, so whatever. Move it if you feel so inclined.

Anyhow, recently I've seen "Downloading" come up during the authentication server logon sequence ("Connecting", "Connected", "Handshaking", before the second "Connecting"). Does anyone know what's happening then? I'm assuming Warden is being downloaded or something similar to IX86BlueDrake is being loaded.

Perhaps they're mini-patches.

Any mini-patch bigger than IX86BlueDrake (comparable, of course) was usually either server-side or distributed directly in the same manner as the content/bugfix patch downloaders are (IE, where the downloader for the patch is downloaded is where the minipatch was placed, and it has no downloader itself). Of course, that's entirely possible though. I'd log packets and see what's up but unfortunately Blizzard had the annoying idea of encrypting their data streams. :(.

[quote author=Joe[x86] link=topic=15658.msg157727#msg157727 date=1157866985]
Any mini-patch bigger than IX86BlueDrake (comparable, of course) was usually either server-side or distributed directly in the same manner as the content/bugfix patch downloaders are (IE, where the downloader for the patch is downloaded is where the minipatch was placed, and it has no downloader itself). Of course, that's entirely possible though. I'd log packets and see what's up but unfortunately Blizzard had the annoying idea of encrypting their data streams. :(.
[/quote]
The authentication server communication is not encrypted.  Only realm server communication is encrypted.

One thing you might consider is using Filemon to monitor traffic into/out of your World of Warcraft folder to see what's being downloaded?

Also, you could consider Denying yourself the Delete permission for your WoW directory so the WoW.exe process is able to create files but not delete them. 

The authentication server response for "Download File" is 0x0a. 

[quote author=MyndFyre[vL] link=topic=15658.msg157732#msg157732 date=1157882913]
Also, you could consider Denying yourself the Delete permission for your WoW directory so the WoW.exe process is able to create files but not delete them.   
[/quote]

Damn awesome NTFS file permissions.

Could be this to, the WoW servers seem to save the macros you create so this could be another thing that it's downloading, that and if your not logged out for some time after selling something it would be reloading the buy-back info too I would guess.

Edit: I would say more the buy-back* than anything though.
Edit2: I could be wrong but I'm pretty sure it used to save the macros server side last I checked it did but now that I reinstalled WoW mine were no longer there.

It saves references to the macro on the bar, but not the macro code itself.

Also, buyback could easily be streamed in-game when you talk to a vendor, just as it downloads what they sell. I'm rather sure it's something bigger than that.

One other thing it could be is interface add-ons.  If you look in your interface folder, there are things from Blizzard.

The Blizzard_* addons are pulled out of the Interface/Patch MPQs on the first use and are not downloaded on the fly, as far as I know.