[//]:content-type-MARKDOWN-DONOT-DELETE Gate Learn has released 3 new articles this week ! The "[Slot Auction](https://www.gate.io/learn/articles/what-is-parachain-auctions/489 "Slot Auction")" is the key part of Polkadot ecosystem, where projects raise $DOT from users to participate in the bidding for parallel chain slots, with their tokens serving as the reward. In the project introduction, we mentioned [Decred](https://www.gate.io/learn/articles/what-is-decred/490 "Decred"), a public chain established in 2016 that is dedicated to private technology. [Push Protocol](https://www.gate.io/learn/articles/what-is-push-protocol/488 "Push Protocol"), blockchain-based decentralized communication protocol, enabling push notifications and messages to wallets.