great post, thanks for writing it! Just a minor correction: the list that I am maintaining is the list of seed nodes, not a list of full API nodes (I should probably do it as well when I find the time to index them). Let me try to explain briefly the difference:

• full node: node that has the complete blockchain (as opposed to light-weight nodes, etc.) AFAIK all Steem nodes are full nodes, distinction comes from other cryptos.
• seed node: entry points to the Steem network, their main function is to be public, connected to the network 24/7, and accept a lot of incoming connections to ensure that people can always join the network (note that this is not a concern for people on steemit.com but only for people wanting to run other nodes) HW requirements are minimal (~2-3G RAM)
• witness node: nodes signing blocks and adding them to the Steem blockchain. These should preferably not be known (to avoid being DDoS-ed), and also have low requirements (~2-3G RAM), similar to seed nodes
• API nodes: this is what you refer to as full nodes, as these nodes do a lot of indexing of the data from the blockchain, digest it, and serve it in a better shape to people wanting to build other apps on the blockchain. Requirements are huge and growing every day, currently >32G RAM already. These are few and far in between, and would benefit from more people running public ones, but they do require some more advanced sysadmin skills than just seed nodes.

(small note: people here might have started to call API nodes will all plugins activated "full nodes", and I might have missed it, in which case you can just ignore what I said :) )