Rands has a rare talent; he explains complex issues using simple words:

So, forever growth must be proven, advertising must fund forever growth, so advertising must continually increase. This means you, the person just looking for Interesting X, must be incentivized to see and click on more relevant advertisements. The services need more data to provide more relevant advertisements and fund forever growth. These services require you to engage more.

They’ve already helped you find your people, and you’ve already helped them out by providing your social graph and high-affinity content for this graph, but they need more because of forever growth. You already see ads, and perhaps you’ve clicked on some of them, but now you start seeing “content we think you’ll like.”

Of course, this is all in the context of him opening a Mastodon account.