Burdensome is an understatement. Between cities, counties and states levying sales tax, there are thousands of taxing entities. In some cases, it's impossible to determine the proper tax rate without a nine-digit zip since city boundaries may split zip codes, meaning city+county or just county might apply in different parts of a zip code area. Forcing the customer to enter a nine-digit zip and then possibly choose between multiple tax options when it's still not clear leads to an incredibly high friction checkout. The main winners in this fight are the companies that provide sales tax computation components or APIs for web services.
However, I think having a sales tax based on location of seller rather than buyer doesn't make as much sense. The big companies like Amazon would find loopholes that allowed them to originate from low/no tax areas and smaller sites without the ability to relocate would be stuck with most of the burden. This just changes the fight from big box vs. internet to small site vs. big site.
I've never needed to add an article to Instapaper from my iOS device, but that's just me. I use Instapaper to sync things I want to read from my laptop to my multiple devices. At least in the near term, I doubt Reading List will do the things I want to do as well as Instapaper.
I wouldn't expect Reading List to take many Instapaper users away, and I think it will drive not-insignificant numbers from Reading List to Instapaper as people want an upgrade. Net gain for Instapaper, hopefully.
"But unlike previous issues such as the senseless iPhone SDK NDA, the majority of the community isn’t riled by 3.3.1"
I think the previous issues have already weeded the field. Those developers prone to righteous indignation have already left. There's another group of apple-fanboys who will never complain. There's a third group that are getting more and more fed up and looking to port to Android, but they're still working on iPhone apps because there's a market. Just like most issues, there's a big quiet middle between the two extremes that is too busy to blog about their ambivalence.
CambrianHouse did this for a while and had a very vibrant community. They shut down and became VenCorps because they felt like nothing was actually getting accomplished.
I also had a hand in the other Minion apps: Pat (a sequence game), rePete (a Simon-style game) and Penny (an interest/future-value calculator). The early apps were little more than "hello world" experimentation with various parts of the SDK, but we're actively developing Reid and some others.