[Tekkub]

WoWI was never able to get a response from WM. Curse was, and WM offered forth a tiny fraction of what their bandwidth was costing. It never went any father, so WoWI and Curse looked into other solutions. This is what they found.

The viability or not of an ad-based model is rather moot now, thanks to Blizzard's new addon policy. Addons must be free to download, so that basically leaves ad-based, donation based, and premium services beyond the free downloads. If WoWI only gave their updater to paying users do you think that could cover the rest of the bandwidth bill? I doubt it personally. Ad-based plus premium may work, and we'll see where that goes with Curse's updater.

The other thing you're neglecting though is that WoWI (and EQI) were able to sustain themselves on an ad-based model for a long time before WM came along.