There are a few big themes around which I like to write.
As the world changes, it gives rise to new and interesting challenges, and creators who will address these with products. This is highlighted in What happens in an exponential world. Others which explore the same theme:
Understanding the world at the broad level helps in predicting what products will be made. For example, in a noisy world, it becomes necessary to make products which help you be calm and focused.
Writing about Product Management helps in learning how to make great products from a broader, more abstract level.
Thoughtful Product Design
I like to see applications of thoughtful designs which make experience better. I am a huge fan of direct manipulation. I also sometimes like to note seemingly little things on products I encounter in real life.
I write about design approaches. I am intrigued by visionary versus evolutionary design approaches. Some people want to move fast and break things, and others want to take a lot of time before giving a product a shape.
Writing about Product Design helps me in learning how to make great products at a more concrete level.