Celsius Network is a platform that uses blockchain technology to enable its users to gain financial freedom by turning away from traditional banking institutions. In other words, it allows its members to borrow, pay and lend through said technology.
When you deposit your coins on the platform, you get interest every Monday calculated on the annual rate and weighted. You can choose to earn interest in the loaned currency or with the platform's token: Celsius CEL. Obviously, when you opt to have interests in CEL, these are slightly more important. There is an advantage to claiming your interest in CEL: the ratio of CEL held in your portfolio can allow you to access loyalty programs that allow you to increase the amount of your interest rates.
My opinion about Celsius Network
Celsius Network is a good solution if you want passive crypto income, you can earn weekly interest up to 15% per year on your deposits and you can withdraw it at any time. Plus, there are no fees, no withdrawal fees, no early termination fees and the app is easy to use. Be careful, don't put all your crypto on the application, Celsius network is not a decentralized application and the risk of hack is not zero. As usual, it's best to diversify your investments.
Other alternatives to Celsius are BlockFi and Nexo, these two applications allow you to do the same thing as celsius.