what does this sentence mean?

The sentence means in a informal/angry manner, that the world is changing it's course from what it was. Eg: we pollute the world much more now, than we did before. That sentence could be used to express how much we pollute the air now days.

Ah this is a statement that I am well accustomed to hearing on a regular basis whether it be through the television or from someone saying it out aloud in public! This sentence is usually used with a hint of sarcasm! Someone might be complaining to their friend about what a sorry state of affairs the world is in and then they might say 'What is the world coming to?' It's both funny and weird at the same time. This is the only way that I can think of when this sentence is used. I hardly ever use it myself as I never make any complaints about the world and the sorry state of affairs that we are all in! Andrew

It means - what is going to happen in the future with all these things that are happening now? It means that the future is being formed by what people are doing at this moment so if we want the future to be different we need to change what we are doing right now...

There is an assumption that the world has changed. The person who's asking this question wants to know what the world has changed into.

I am not a native speaker of English myself so my interpretation of the idiom might be wrong. But usually people say this sentence when they are shocked at the changes that have happened to their situation/world (usually for the worse or something negative). Therefore they are wondering what this world is coming to (or what the world is becoming).

The phrase you are referring is an expression of bewilderment or surprised in a situation or event that is not foreseen or unexpected in a given context. Basically, this phrase is used by people when they don't understand the whole concept or what the whole idea is all about. It is usually expressed in an exclaimed tone and in a manner of disbelief toward the situation - usually due to a twist in an ongoing event.

It's an exclamation. It implies that everything is going downhill and getting worse. Someone might use it if, for example, an old lady is robbed of her pension, or to describe some other morally degenerate act, crime, terrorism etc.