Ah, finally someone actually gave me some context about the yellow hex nut thing. Apparently, alvin.social is an ad funded Mastodon node where you pay to disable the ads. Also, it doesn't seem to mention the name of the Mastodon network anywhere in its very rudimentary marketing.
Initial gut reaction: This is sneaky in a pathetic way.
Second thought: If you were a business and wanted to run a Mastodon node without losing money on it, how would you do it?