Yes, or local storage — they're essentially the same as cookies in terms of UX. I don't want to continue where I left off on another machine — right now I just

Yes, or local storage — they're essentially the same as cookies in terms of UX. I don't want to continue where I left off on another machine — right now I just want to see the thing in the first place. If you expect people to sign in before they can see your content, presumably you expect they already know that they want your content — enough to overcome the hurdle of giving access to the 3rd-party account that you assume they already have or are willing to create. Progressive enhancement!