It's easy to talk about material goods as being "unnecessary" especially if they do not contribute to one's physical safety or health, like shelter, food and water.
For better or for worse, though, we are a consumer society and some things almost start to seem to become needs not because they contribute to our physical safety or health but because they contribute to our ability to integrate socially.
You may not "need" the latest smartphone but at the same time, especially among younger people, you could almost say you need to have a smartphone capable of accessing social networks in a reasonable manner because it's extremely difficult to integrate with many peer groups without one. You will not be able to participate in group dynamics or posses the same social information as other people.
The same thing could be said (more tentatively, because there are other outlets) about Netflix. If you're not able to engage with people socially because you are unaware of the types of programs they consume and cannot participate in discussions about them you are also hindered in group dynamics.
Outside the electronics/media sphere, you can make similar judgements about clothes. You don't "need" clothes that fit a specific fashion or brand paradigm -- you can buy used clothes or dollar store clothes and meet the minimal functional needs for clothing. But style and manner of dress is very important for engaging in peer groups, and like it or not people are in/excluded or find it easier or harder to engage in social activities if their mode of dress is compatible with their peer groups.
Now it's easy to make a lot of value judgements -- especially about social networking (the companies, phenomenon, etc) -- but their existence, usage and impact on social life is a reality and at some point I think some of these things become needs for reasonable social integration. Excluding them because they don't meet some minimalist description of "need" starts to sound myopic and mean spirited because I don't know anyone who just lives based on minimal need.