How do you know someone has an iPhone? They'll tell you.

What a nice populist sentiment. Also: Completely and utterly wrong.

The guy who took the video doesn’t mention his iPhone anywhere, not in the title, not in the video description.

The specific device is irrelevant and so is your question.

The headline “Smartphone Films Final Discovery Launch From 30,000 Feet Up” would be just as good but complaining about the additional (albeit irrelevant) information in the real headline seems just strange.

The information in the headline that this was taken by a smartphone is certainly valuable – you immediately know that this is not about professional video footage for example from a NASA plane but amateur footage taken from a commercial airliner which is a lot cooler.

Does it really annoy you and all the people who upvoted you so much that the writer of the headline (not even the guy who took and published the video) went that small extra step and mentioned the specific model of the device used to capture the video and not just the general category? Why exactly?

You don't seem to understand people that suffer from gadget inadequacy. They look at their own and other people's choices in purchasing consumer electronics as a reflection of self worth.

What indicates it was an iPhone anyway? The video doesn't say that. Is there a clue in the format?

iPhone is web scale. That and MongoDB.

It's not but it's relevant in the perspective that fourspace says further up.

It's very relevant to getting enough attention to come on the front page and grab more votes.

As does pointing out that you could do this without an iPhone. Clearly these are the sort of thoughts which can only be described using a qwerty keyboard, right?