Daily Poll: What to consider when buying video streaming stocks?

Many consumers developed a strong appetite for live video and online digital media over the dire months of lockdowns. 
Platforms like: 
Netflix $Netflix (NFLX.US)$
Disney+ $Disney (DIS.US)$
HBOMax $AT&T (T.US)$ have grown strongly over the past year.

However, $Netflix (NFLX.US)$'s 25% dip on Jan 21 was like a warning to all investors. The number of subscribers won't grow forever.

Billionaire investor William Ackman said his hedge fund had acquired 3.1 million shares of $Netflix (NFLX.US)$ attracted by a recent selloff of the streaming giant's stock.

Except for the price, what do you think is the key reason pushing Ackman to buy Netflix? 

And what about you? What matters the most when you consider buying these stocks?