I stand alone in a world full of people

If you think about it this is indeed true for everyone, ultimately you have to use your own feet to stand, and nobody elses. But the expression points out that some people still feel alone in this world though its completely full of people.

I wonder is it because they do not talk anymore, but surely they must for how else will day to day business go ahead.

To those who feel this way perhaps loneliness is just mere illusions of being dependent and unable to stand on your own feet. Why must you wait for that someone to arrive for you to live your life. They mean happiness to you, but can you also not find happiness in yourself? There are so many out there that feels this way.

So if you ever feel lonely, then perhaps you should say hi to someone, who knows you could be lonely together?