WikiTech
The WikiTech wiki at https://wikitech.wikimedia.org/wiki/Main_Page is really a wonderful resource to the Free Software Community. (And there are others like the Mozilla Foundation's Developer Network https://developer.mozilla.org/en-US/)
I have no intention of duplicating the knowledge and effort there. Instead, I want to link to it, and perhaps distill or expand on content there as warranted. For example, In 2016, I want to become more involved with the MediaWiki foundation and projects so it's important to be aware of and participate in things like the Tool Labs