In case you haven't noticed, there's A LOT of stuff on the internet. Even when discounting all the gibberish there's a lot of stuff worth reading, either for education or entertainment or edutainment.
Of course, there's a difference between a) stuff worth following, b) stuff worth reading and c) stuff that you should never, ever miss.
I have about 300 blogs in my RSS feed but there are only a few that I always read when they appear. Here they are, in no particular order.
Wayne Hale's Blog
The former Space Shuttle flight director and program manager (waynehale.wordpress.com) gives us historical and sage insight into space flight that only someone who's "been there" and "done that" can do. Hale doesn't write only about the machine and its technology; he tells you what goes on in the minds and hearts of those involved.
Whether you're an armchair or professional scientist, anyone with an interest in the secret life of fluids should be reading the blog with the name I can't repeat to my mother, FYFD (fuckyeahfluiddynamics.tumblr.com). Fluids do some crazy things and with a video or a photo and just a paragraph or two FYFD lets you in on their secrets without killing the wonder.
Every Friday the Cartoon Research blog posts another in their Animation Anecdotes series (cartoonresearch.com/index.php/category/animation-anecdotes) . This weekly post delivers paragraph-sized stories about the people and productions from the world of animated films. There's always something interesting, always something new. Like the one about Speed Racer and Kurosawa.
The Aviationist (theaviationist.com) never fails to delivery quality aviation glamour, news, and stories. Come for the pics and videos. Stay for the news and analysis.
It might seem morbid to be a fan of a blog about "nuclear secrecy past and present" but my non-fiction book reading largely feeds my interest in the Cold War of which nukes were a big part. Whether it's about bomb design or the bomb's designers, Restricted Data (blog.nuclearsecrecy.com) covers it all. And let's not forget NUKEMAP. (See the link at the site.)
Wajobu (wajobu.com) writes about music like it's nobody's business. Fortunately, he also writes about music I like such as progressive rock and ambient. And yes, he's a friend of mine.