Is it trademark infringement if startups use well known brands in their slogans or high concept pitches?

Question

We have got some advice that it is useful to use popular brands to illustrate your business model.
For that I have even found a couple of examples of successfully funded startups on Angel.co - such as "Viddy - Instagram for videos" or "Pinshape - iTunes for 3D Printing". Why don't these startups infringe trademark rights by using instagram and iTunes for their own purposes?

Here are the examples I mentioned:

https://angel.co/pinshape
https://angel.co/viddy

or

Answers: 2 public & 0 private

13ac82468e
Patent Attorney

Simon I'd like to ask a sample like:
"john smith Hotel
Your new Hilton"

I see this as an infringement. I saw the samples of question. I could not accept them as infringment but my sample must be.

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