The professional blog is a good way to :
- share valuable content to others from your field of expertise
- connect with other professionals who work on similar problems
- share ideas and expertise
I personally use feedly to subscribe and read lots of other programmers articles. There are priceless blogs in the net like :
- Troy Hunts blog
- Martin Fowlers blog
- Rowan Millers blog
- and many many more…
What I believe one should post on his blog? Post about “things” that you have :
- encountered as a problem to solve or came up with an interesting scenario
- done extensive search about it
- not found anything suitable as a solution or ready as a whole to this date
- produced as real solution from which other developers can profit
All the above mentioned blogs are of that type. This is why they are so valued among developers – they give real professional value to everybody.