My answer might be a light bit off-topic, since it’s not exactly for "learning how to code", but since it might interest people, let’s share some
First things first, follow Confreaks on Youtube. They collect/regroup many tech conference recordings, so it’s a great way to be exposed to a ton of things. Depending on your domain/interest, you’ll ignore many of them, but from time to time you’ll find a gem. In other words, since it covers many languages, the signal/noise ratio might not be the best for you, but it’s really quick to parse to see if there’s anything new you’d like.
More systems-related, follow the Usenix youtube channel (I enjoyed many talks from SREcon, LISA or USENIX Security confs over the last years!)
It’s probably obvious because it’s so well known, but starting with all Rob Pike (no link, because you can either search twitter or youtube) contents is just great. (both blogs posts and conference talks). I mention to add a little detail: one thing I love with Rob’s knowledge sharing sessions is that, most of the time, it’s both easy for newcomers and has some depth, so that if you watch/read it again a few months later, you’ll learn something more (in other words, do check the archive regularly and do your homework, there’s a lot of great stuff!)
You can then follow Franscesc Campoy on twitter (francesc) (former Golang dev advocate for Google), since he’s pretty active, you’ll get slowly exposed to other great sources and be able to pick your favourite ones. (and his talks are also with your time!
I also really enjoy Dave Cheney: great talks, low volume but always interesting!
Raymond Hettinger on twitter (Python core contributor) often share great small bites of knowledge. I always learn new things!
PyCon accounts (problem: there are several accounts, so you might need to search regularly). But catching up with previous and current PyCon talks is a great way to be exposed to clever things
Cindy Sridharan is probably my the most valuable account I follow on Twitter. I learn so much from her. Always awesome pieces of knowledge, great books/papers/posts recommendations... If I could follow only 1 twitter account, it would be her!
Bryan Cantrill (CTO of Joyent) is an awesome source of knowledge. Check for his talks! (he did many, and I enjoyed them so much)
Jesse Frazelle (former Github, contributor to Docker, she implemented the security bits in Docker). If you’re interested in the low-level parts of your stack, how containers work, how to secure your systems, she is often mentioned for good reasons!
Charity Majors is very active and I love how the express her views (I’d love to have such a manager!). If you’re interested in engineering/management paths/careers/ladder and all the challenges, her blog posts are absolute must-reads. Other content is about systems observability (I wasn’t sure in which category to include her, and put her name here just to balance my lists ;-)
Will Larson ( twitter: lethain , blog ) many many great posts. I am really looking forward to reading his Elegant Puzzle book (should be out in a few days!)
I probably forgot many, but I postponed my answer here, trying to think of all the great sources...and hadn’t the time to clean the list, so at least this is my best start and I really enjoy all the sources I shared here. I will probably edit it over time as I remember other people (and will feel ashamed to forgot them in the first place!)