How many nodes are they being sent to now
All that they're connected to.
what's the importance of a node?
The nodes are the network. It started with Satoshi, his node was the first. Slowly, more people joined the network by connecting their node. Every new node is someone extra that can send or receive BTC, using their node.
If you're thinking "I send and receive BTC without a node of my own", then that's because you're using a service that sends and receives Bitcoin for you, using their Bitcoin network node.