Note: Okay, officially finished as far as a text write up.
What are Nodes?
Every city is a node and each has quite a few locations around it that are associated to that city. Nodes are farms, mines and other useful locations.
How to get more out of a Node?
You will have to spend contribution points to have access to the node benefits and to be able to link it to other nodes. Most cost one contribution point but some are 2 or even 3 for the initial setup. You can contribute more over time. If the node you are putting contribution into is linked to a city you contribute to, the arcing line connecting them will turn from white to yellow. You will see all connection lines for a node as soon as you contribute to it.
Now here is a fun tidbit that goes with nodes as well. You can level them slowly by pouring energy into them. I would recommend any node where you will be farming, harvesting, have workers, etc. leveled as it will increase your success and output further.
Linking the Nodes
As noted above putting contribution into a node will link it to any nodes it is connected to that you have set for contribution. Definitely explore to find all your nodes as there is more than one way to get across the map to connect cities.
The fun part is that every node must be reached in outward steps from the city it is associated with. You cannot pass over from Olvia to Velia related nodes and continue the path. Once you have the Olvia chain to the end you must run into Velia and work you way out through its nodes. You will know when you can't do anything with a node when it says you have to go to a previous one. When it tells you this figure out if you see a node between you and the city that is not connected or go exploring if you don't see the node at all. Some of the nodes are fun to find! However, there is a cheat, the blue path and you can even hit T to run to it! This will come up when you try to contribute to a node you can't link yet. I have to fiddle with this more, but I think it will override the blue path trail you might have active. (Quick note - quests and locations can be marked and give you a safe road path to follow to reach them.)
Why Link Cities?
More money and you can start doing trading quests between cities. It is recommended to go the cheapest contribution point between cities to get more bang for your points. Once you get more things going you can link up the world if you so desire. But until then link what is needed for the trader and the cheapest path to the city.
Traders like Node Links
You will need to find the trader in each city and find out what specific node related to the city he wants linked to give you the full price for items. If you do not have this node linked to the city, he will only give you 30% of the real price. You definitely want him at 100% because he is the guy that will buy your fish and other interesting items only traders will buy from you. Fishing is a very lucrative money maker in this game and super easy to do, but not worth it if the trader is not activated to full for you.
Account Based
As mentioned below in a reply before I could get this done, node management is account based. What one character opens up, all have opened up. And it does not matter what channel you are on the server for this information. The channel only matters for grouping with the guild and friends to do things.
Making alts is a great way to get more contribution as they can do the contribution point quests all over again. This game is actually very alt friendly and you get some synergy out of having alts working on things.