What’s the point of retail sentiment? It helps judge whether a stock has gone viral.

Suppose there are only about 300 traders on Earth in total. For a given market, most of the time it's played by roughly 100 people, with some coming and going—anywhere between 90 and 110. Then one day, a flood of new players shows up, bringing the count to 200 active players, and it keeps heating up until 250 are in the game. That's what we call "breaking out of the niche."

When there are 200 potential players and only 100 actual players, the potential players can easily take over the positions of the existing players. But when potential players have dropped to just 50 while actual players have grown to 250, the remaining potential players simply can't absorb the selling from everyone in the game.

In the old saying, when the grandmas at the wet market are all excitedly talking about it, that's a sign the momentum is about to fade.