The Evaporative Cooling Effect describes the phenomenon that high value contributors leave a community because they cannot gain something from it, which leads to the decrease of the quality of the community. Since the people most likely to join a community are those whose quality is below the average quality of the community, these newcomers are very likely to harm the quality of the community. With the expansion of community, it is very hard to maintain the quality of the community.

Once a post goes viral on Twitter, Hacker News, Reddit, or anywhere else off-platform, it has the potential to form a “Katamari ball” where it gets upvotes because it has upvotes (which means it gets more upvotes, because it has more upvotes, which means…well…you get it). This is also known as "the network effect", but I feel a Katamari ball better illustrates it.

After all, the best messaging app in most countries or continents is the one most other people are already using there.

“INFORMATION RULES”—published in 1999 but still one of the best books on digital economics—Carl Shapiro and Hal Varian, two economists, popularised the term “network effects”,

By bringing both designers and non-designers alike into Figma, they create a cross-side network effect. In a direct network effect, a homogenous group gets more value from a product as more of them join. In contrast, a cross-side network effect involves two (or more) distinct groups that grow in size and value as the other group does, too. Figma’s cross-side network effect between designers and non-designers is one of the primary and under-appreciated sources of their compounding success over the last few years. As more designers use Figma, they pull in the non-designers they work with. Similarly, as these non-designers use Figma, they encourage the other designers they work with to use Figma. It’s a virtuous circle and a powerful compounding loop.