I have hosted my World of Warcraft addons at Curse.com for as long as I’ve published addons (not long, actually). And for as long as I’ve known about it, I’ve used WowMatrix to keep all the addons I use updated because (a) WowMatrix had a Mac client, and (2) it aggregates addons from many publishing sites, not just Curse.
For quite some time, there’s been drama between Curse and WowMatrix. I am told, but this all happened before I was paying attention, that WowMatrix used to list the addons without links back to the author’s websites and stuff which, let’s be clear here: that’s really a bad thing. WowMatrix are also reputed (by Curse and WowInterface) to have done other asocial things, but as I said, that was before I was paying attention so I have no personal experience with it.
So now Curse and WowInterface have teamed up to implement some form of blocking so that my WowMatrix client can’t download addons from them any more. Crap.
Curse is certainly allowed to do that; it’s their service and they can provide it however they want to.
I however don’t have to like it, and will be moving my addons away from Curse to GitHub (probably) and having my WowMatrix link updated. It is really a trivial thing, but there’s not much else I can do (besides update my router to block the ads displayed in the Curse Client and poison the Curse addon data that they insist on reaping from my gameplay).
I also hope that WowMatrix is working on figuring out a way around their blocking.
EDIT: Upon further reflection, I have to refine my position a bit: I do not hope WowMatrix figures a way around this. Curse and WowInterface certainly deserve their ad impressions in exchange for aggregating and hosting their respective addons. I still think there is a significant amount of consumer surplus to be had here, though, in further aggregating the updating process. I've started building a proof-of-concept that will (a) auto-update all my addons from whatever source, and (2) will display the hosting site's ads and pass click traffic to them. WowMatrix is definitely in the wrong to obfuscate the ads from the hosting site, and I won't make the same error.