I live in an area that can best be defined as "mixed". The gentrifiers came through during the go-go real estate boom and try to force the white trash and minorities out, but the market crashed before they were able to finish the job and now there are clearly identifiable subcultures within a ten minute walking radius.
I have come to the conclusion from my observations in this mixed bag is that the cell phone and internet connections are the clearest indicators of poverty. When I talk with A (poor dude, out working on his car) the cell phone goes off and he claws at his pocket like a junkie going after a fix. The immediate conversation that he was having with a human being is unceremoniously trashed. This behavior also seems to be widely practiced by his peers in the neighborhood.
The gentry take a different approach. They are much more likely to mute their phones and ignore it if they are in a conversation. Not always but the greater bulk of the time. My favorite is a business type who's phone rings with the the "Money" tune from Pink Floyd when it is a business call. He will always look you square in the eye, says "business", tells you he is going to take the call and walks away. He ignores the regular ring.
The other thing that shocks me is the amount of money that the poor folk spend on their phones. The unemployed erstwhile mechanic had an iPhone. The businessman had a beat up old razr.
I am thinking that the primary reason behind this differing way of approaching these odd appliances is simple. The po' folk cling the phones and cherish them because whoever calls has to be in a better place than the suckage that they call a life. The gentry knowS that whoever callS is probably not going to make their life better, they can safely ignore it.