Oh, I don't mean that scale is the only factor. Clearly, the structure of Mastodon is way better than the structure of Twitter. But, I'd bet that if Mastodon was as big as Twitter, if it was that juicy of a target, it would have way more spam than it does today.
I both agree and disagree, in that;
- the amount of spam on Mastodon will surely increase in amount proportional to the size of it's network.
And
- Mastodon users won't usually see that new spam by the dynamics of the current system because we're only shown content from sources we explicitly follow.
You only see who you follow, and there's no like/karma/upvotes algorithm.
Everything is sorted chronologically, and if anyone tries to "game" that by posting too much, they'd get unfollowed and/or banned.
Mastodon is a nurtured cultivated twitter.
Personally I follow the CSS/JS/TS community (for work), the gamedev community (for fun), and the space community (for passion)