I agree that whitepapers are a good source for information, because in order to write a whitepaper that will be used to prove the worthiness of an investment in an ICO, quite a lot of research has to be done, and the pressure is on for accuracy.

Hackernoon and Medium often have good articles.

One of my favorite sources for serious reading about blockchain technology, however is Google Scholar. This is because academia is a good source of ideas for applications of blockchain because they are often unbiased and funded by research institutions.  You can find some interesting papers there, such as the HoneyBadger BFT project - many, many others. The writing is also a little more serious and useful from a technical perspective in my opinion.

Articles I don't like are these little clickbait articles on many of the "crypto" sites which turn out to be thinly researched and created from a specific point of view or thinly disguised advertisements. For those,  if I can't resist and and end up on one of those articles, it's not a total waste because you can scroll down to the comments, which are often better than the article!