One of my favorite things to read online are the developer postmortems for games I've played. Getting to learn what it was like for the people who made games like Age of Empires 2 is both entertaining and useful, in an educational sense. Developer blogs, especially for indie game developers, will often have posts about the development process of a game, but for some more popular titles you have to read an article on a site like Gamasutra to get a glimpse into the development process.
The sorts of things you pick up on by reading postmortems vary based on the developers who are being interviewed or writing their experiences, and what specific project they worked on. It's a bit like reading the biographies of successful people (for whatever your definition of successful is), sometimes you'll get useful little gems out of their experiences, and other times you won't. Either way it's usually an entertaining use of your time, especially if you've played the game the postmortem is about.
Mostly I read game postmortems for fun. You certainly won't learn as much about the technical aspects of software development as you would by just sitting down and writing code or working on a project, but there are other lessons on things like keeping productive, managing teams, working with partners and the business aspects of games. Those are helpful things to learn that you can only get from reading about other people's work experiences. It's like reading a really good non-fiction book on a specific topic, you absorb the knowledge of the author and incorporate the lessons into your work.
Blog posts written by game developers, indie or otherwise, are often interesting too, but I think a postmortem format can provide more value because it focuses on what happened, what went right and wrong and what can be learned from the experience. Reading a series of regular blog updates on a game's development progress or release won't usually be as concise or focused, I've found.
My favorite site to read postmortems of popular games on is Gamasutra. They've got a whole series of these articles, and this is where I first heard the term postmortem applied to a software project. Game Developer magazine also collected a series of its published postmortems into a book, which is a bit expensive to buy brand new but has a Kindle version that can be rented for cheap.
The Super Meat Boy and Age of Empires 2 postmortems are what I recommend reading if you've never read any before. I thought both were interesting, and both of them made me feel more than a little lazy and unfocused in comparison to the people who worked on those projects, because I am.
On an off-topic note, it's been way too long since I last sat down and worked on a hobby game project. Almost a year in fact. Given all the other stuff I have to do and want to do, I'm not sure when I'll manage to sit down and really write a new Flash or Pygame game again. Reading game and software development posts from other people on places like Hacker News and Hobby Game Dev helps me feel like I won't be too lost when I force myself to sit down and work on a project again. I'll be somewhat lost when I stare at game code again though, for sure, but reading about people who are actually working on cool projects at least lets me feel like I'm still learning something about game development.