The Stellar network is a cryptocurrency platform on which we can create accounts and perform transactions. It's a bit like a bank, except it's public and decentralized.
Because it's public, each of us can contribute to the network by various means, like programing services such as this one. We can also emit our own currencies or tokens, build secure voting systems and other things to be invented. :)
Because it's properly decentralized, it's protected from anybody that could want to disrupt or hijack the network for its own benefit. Our funds are secured by cryptographic algorithms and resilience. Resilience means that several nodes on the network have a full copy of the data, and that the various independent nodes have to agree together for the transactions to be performed.
In order to sign a Stellar transaction, you need to have an account with a minimum amount of the native currency, called lumen (XLM). At this time, the minimum amount is 1 lumen, valued between $.20 and $.50. Once in, you'll be able to close your account and get your money back at any time, if you wish to do so.
Cosmic links are normal web links that describe a Stellar transaction. When you click on them and own a Stellar account, you're given the possibility to sign and send the transaction to the network. Those transactions are for payment but also for currency conversion, change in account settings or sending short messages. Cosmic links may looks like: https://cosmic.link/?setOption&...
We wish you a happy discovery :)