> We are living through the latest stages of the online advertising bubble, as available high-quality ad space is shrinking, leading to a decline ad space quali

> We are living through the latest stages of the online advertising bubble, as available high-quality ad space is shrinking, leading to a decline ad space quality, and a decline of ad efficiency. I don't understand how it's a bubble since the decline has been steady over the last few years. A bubble is spectacular, not gradual. A bubble expands and then suddenly and unexpectedly pops. A bubble ends in a steep and surprising decline. All of the trends here with fraud and growing use of ad-blocking software have been on the horizon for a very long time. It doesn't sound like a bubble, but talking about "bubbles" gets lots of clicks.