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Afaik, upvoting will only work for a while -- I believe the sorting algorithm uses time as a factor, to allow newer comments to bubble up above higher-rated ones.

Even better - a small "context" link you can hover and get the context right there on the front page.

Additional context needed: is there something new in iOS 9 that makes ad blocking possible?

Yes, iOS 9 introduces a new content blocking API making ad blockers in Safari possible:

https://developer.apple.com/library/prerelease/ios/releaseno...

The device has to be a 64-bit CPU though. So if you load iOS 9 on an older iPad or iPhone, then you will not get this feature.