There's a fun little browser extension called "StreetPass for Mastodon", which notices if websites you're browsing have official Fediverse accounts:
When you check your StreetPass, it will show you a list of all the official accounts from the sites you've been browsing. It does this offline, your browsing data doesn't leave your machine, and the code is free open source.
Official accounts are detected by verification (more info: fedi.tips/how-do-i-verify-my-a…).
How do I verify my account on Mastodon and the Fediverse? | Fedi.Tips – An Unofficial Guide to Mastodon and the Fediverse
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