IF <-- bold) this is a bubble, you will find that companies that had solid earnings had no earnings at all. There is a lot of spit swapping going on where many companies with no way to make revenues are using cheap investment money to advertise thus making other companies seem much more profitable than they really are. You'd also find that companies were using accounting tricks to cook the books.

lastly, earnings may 'look' great, but when they have to spend ever increasing billions of dollars to buy out their competitors to remain a viable business, you'd have to back out those purchases (which people usually dont) from their bottom line.

example: facebook pretty much had to spend nearly 20 billion in capital to remain relevant. they did so by diluting their existing shareholder's value of the company by about 20%, which is not a sustainable thing to do.