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MyETHMeta is a completely decentralized metadata service for Ethereum. Your profile picture and profile data are assigned to your Ethereum address instead of your e-mail address. The metadata assignment is managed by a smart contract on the Polygon chain. I choose Polygon because of the low gas fees. The metadata can be stored on any URL. The storage can be a centralized server or any decentralized storage like IPFS or Swarm. The metadata itself is a simple JSON file. It is based on PortableContacts (like Gravatar), but you can freely extend it by custom fields.