I think they still matter. Manners are basically social codes that we use to display a respect (or disrespect) of each other. Young people may not use these codes in traditional or historic ways but respect codes still exist and I would still call these manners.

Anna,

How is it you are able to reach into my mind and choose topics that i spend endless hours pondering and eventually, sometimes disastrously testing in the real world?

Having done so with manners, am convinced that manners/codes first emerged with language and demonstrated whether an individual was worthy-of-belonging within a tribe.  Those who didn't 'get' the codes were cast out or put at risk and died out. This scenario is as real today as ever and plays out with the universal fear of rejection.

Proven in New Guinea, Hawaii and other areas where we can track new colonies and tribes, it takes only  one generation to lay down new rules for grammar and customs.  E.g. Pigeon-English has rules, yet sounds like Jar Jar Binks jibberish to  capital city dwelling British/American/Australian speakers.

4 years ago I was on a flight to London on China Air, I sat next to a runny-nosed Chinese kid who kept sniffling and snorting loudly.

For me, it started to turn my stomach, especially 4 hours of it to Dubai... I eventually told him to stop and blow his nose, I even complained to a lovely Chinese stewardess.  Bottom line:  To blow his nose would have been deemed bad-manners in traditional Chinese society,  the pretty Chinese Stewardess knew that, he knew that and i didn't. E.g - I didn't 'get it'.

It's stuff like that keeps lines drawn between tribes/gangs/societies/generations/socio-economic groups...

Back track about an ice age - Bear in mind, cold nights, infant/adult mortality, saber tooth tiger and rival tribe attacks. These codes which would have definately included: basic customs, etiquit.  Certain looks, movements, personality, the ability to hold a conversation building to humour and tribal fireside story telling /listening. 

The ability to convey intentions/personality/customs/codes/ share humour and good feelings - arose quickly (within a generation) then got refined to veil the terrors-of-life and clearly define the tribe. I am convinced, people that didn't 'get it' died oout for the most part.   It is with in this context that organized thought and religion  'of legions', are born, like Old Testiment rules of cleanliness and customs etc. Tribal wisdom, strength in numbers, safety and a safe bet for the future.

As society developed, humour and conversation developed into currency.  Hell, when you have a life expectancy for 25-35 years, what else really matters past a full belly, and some shelter? 

Humour, personality, conversation,  an ability to hold court masterfully etc. That's where, history shows folks like Casanova or Saint Germain creating legends and a living though being magnetic story-tellers and masters of custom in courts around the world.  Each court being the echelon for a societies customs/codes evolving into diplomacy etc. 

St. Germain may have mastered this to the greatest degree of anyone.

As Casanova, Germain or any con-man knows,  when in Rome do as the romans, refine it and be the best Roman out there.

"The youth today have no respect", once said Socrates,  is because like language the codes evolve and the result is the generation gap.

Perfect!

However, me thinks that there were way, way, way, tougher times than today.  With mass media resulting in language/code-standardization - if Casanova or Saint Germain were around today they would be pop stars, presidents and CEO's of PR companies, web enterprises or movie studios they would shape shift, adapt and leave today's best for dust.

Manners do matter but the codes and norms that define and dictate what manners are depend entirely upon the culture that they come from and the generation who help enforce them. I think we are losing the art of good etiquette, or arguably the art of good etiquette is changing. I lament this, others (notably my father, who cannot help but eat in the most appalling and infuriating manner), will celebrate it and mark the demise of this so-called “good” etiquette as the seal upon a new epoch of human social customs.
Like fashion, manners can only evolve and move with the times. The effects could be disastrous or inspirational. However no matter how remarkable or unremarkable our rules dictating respect, conversation, dining and other protocol might be, it is without doubt that previous generations or different cultures will always bemoan the loss of civilized society. As the youth of today there will come a time when we too will yearn for the way things once were and remember an age when “good manners” still existed.