Inherently Concerted: Sabo, Inc. d/b/a Hoodview Vending 359 NLRB No. 36 (2012)

Can a simple discussion between employees be protected concerted activity under Section 7 of the NLRA?

Yes.

If employees are discussing a "vital term and condition" of employment, they are protected when they talk to one another about it.  These conversations are "inherently concerted."  It does not matter if the speaker or the listener agreed, or whether the speaker was trying to change things or persuade the listener. This is a bright line rule.  With one exception...

What are "vital terms and conditions of employment"?

According to the NLRB, they are the terms/conditions that you might generally expect employees to seek unionization about or engage in other group action about.  These are the basic ingredients, the flour, eggs, and sugar if you will, of organization and collective action.  So far, the Board has identified wages, work schedules/hours, and job security as "vital terms and conditions".

Are there others?

 I don't think that the list could be too large, but some other basics might make it.  For instance, safety would be a good candidate in my book.

The Board lays out the history of this doctrine and its justification in Hoodview Vending, 359 NLRB No. 36 (2012).  It is well worth the read, but in case you would rather watch, I have put together two animated scenes (30 seconds each) that depict the essence of the relevant facts.  The first one shows the essence of the activity at issue and the second scene captures essentially what the Board believed happened.

The Board held that because job security is a vital term, the conversation was inherently concerted and therefore the discharge was unlawful.