Ethereum is a blockchain application platform. Imagine a world where a block is a version of some code that runs when it is called upon, and these can be chained together to create more complex applications.
This list intends on providing a summarized version for anyone interested in learning how to create, manage, and even make a living creating distrubuted applications using Ethereum.
When should I implement blockchains? This answer is a great overview of blockchain concepts and comparing Ethereum to Fabric. It's a good idea to know when to use one or the other.
What are 'smart contracts' - A newbie intro to thinking with blockchains
Learn Solidity in Y minutes - Learning by reading more Solidity code
Dappsys - The best way to learn sometimes is to read code. Dappsys has a ton of example code for common concerns you can use right away.
D'app software patterns - Software patterns for distrubuted applications
DEVCON1 talk on patterns - In the flesh
Ethereum YouTube channel has tons of videos on virtually any subject.
Q&A on governance trade offs is a talk about how Ethereum is the one of the first times engineering disciplines and democratic ideas converge.
Sublime Text with Ethereum plugin
Webstorm also has plugins available.
ether.camp Even Microsoft thinks the winds are changing with their online IDE solution
ethpm is the Ethereum package manager
Parity Easy cross browser solution for browsing distributed apps
Meteor - Javascript platform that can be augmented for distrubuted apps.
Web3.js - Ethereum JavaScript API
TestRPC For building a mock RPC network
Solium linting for solidity code
Embark - Embark is a framework that allows you to easily develop and deploy Decentralized Applications (DApps).
/r/ethereum on reddit
Ethdev - Great focused community eager to help
Stackexchange of course!