I used to check out lambda-the-ultimate.org for PL though it seems to be mostly quiet. Interesting discussions and references to papers. I keep an eye on new languages by checking their forums etc. E.g. nim, V, Julia, K etc. I never took a shine to Rust! I currently like V and should write some non-trivial programs in it to get a feel for it (IMHO this is the only way to really learn a PL -- until then you don't really know what things are easy to express, what are hard and what are some gotchas in the language). The main issue I have with newish PLs is that they all play in the same playground and not very innovative.
On OSes, I mostly check out papers these days. In the old days Usenet groups were good. If I hear about something new OS related I google and find related papers. I scan hackernews at least once a day as there are links to interesting articles and some discussions are good.
Though one has to wade through more and more of low quality/wrong/fluffy stuff before you find something good. We need a data "centrifuge" to separate the wheat from the chaff! IMHO there is still space for a "curated" internet.