Sometimes I get asked, "Why do you do it?"
"How much time does it take?"
It does require significant time. I estimate I spend an average of 30-60 minutes per post and I try to make one post per weekday.
But, why do it?
1. Its fun.
Why? Probably because I like learning and understanding things. If I have to write something concrete about a paper or an idea then I am forced to understand it better and more carefully think through the basis of my opinions.
2. It saves time.
-On career advice I don't have to keep repeating myself to students and postdocs. I can just refer them to posts on the relevant topics.
-I (or a reader) may detect mistakes in my thinking, that might have gone undetected for a period, wasting time.
-blog=Web log=diary=note book.
It is a good source of notes. Searching old posts I can find information and ideas I have already forgotten about or might be lost otherwise.
-hopefully it is a useful source of information about me (both science and philosophy) for prospective students, postdocs, and collaborators.
This will attract the like-minded and scare off those with different interests and values.
Finally, progress and achievement in science is very slow.
Making a post gives me a tangible sense of achievement for each day.
So even if no one read it I think I would still do it. But, the positive feedback I get is encouragement to keep going. The best encouragement is when a post generates some constructive debate and discussion.