Hear me out. Mastodon Gold is just a joke, perhaps a pun on the bird company's color thing.

Such example of these joke posts are reactions to specific photos or videos, in which you can't see them because the post requires a Mastodon Gold account to access them.

This is, again, a joke. The Mastodon project is licensed under AGPL 3.0, which the original writers of this license (the FSF) are the ones who dislike third-party advertising, paid subscriptions and so. And we currently see that the authors of Mastodon still have no plans to introduce Mastodon Gold.

Or in other words, with a free, regular Mastodon account you still can have these for free:

• Custom emojis (which could be paid in Discord and LINE)
• View posts longer than 300 characters (as the ActivityPub protocol supports)
• Follow accounts from different servers
• Have that important blue checkmark (as now more and more Mastodon servers add this as a server-wide custom emoji)
• No advertising

In case you're interested to support the federated social media you know and love today, many servers/instances/clans are open for donations and sponsorship (contact admin for details), and you can sponsor the Mastodon foundation too.