Streamr is a decentralised network powered by people the world over. By operating a Streamr node you help to secure the network with your latent bandwidth.
You'll need to create an Operator smart contract pair it with your Streamr node(s), which can be run on a cloud hosted VPS, on your laptop or even on an idle Raspberry Pi.
Follow the instructions here: How to become an Operator.
Not at all! You can earn as a Delegator that provides passive liquidity for Operators. Delegators earn by delegating their DATA tokens to Operators that in exchange share a cut of their earnings.
Learn about delegating here: Delegators.
The complete DATA tokenomics will be in released at the "Streamr 1.0" milestone. Streamr node operators will secure and relay data on streams associated to Sponsorships. Delegators delegate to Operators and earn a revenue share of the Operator's work in return.