Every Developer Should Have a Blog

Because they can write small snippets of code or commands and refer it.
Because they can document a tough problem they solved (for others and for themselves in the future).
Because they can identify their own growth by looking at the old posts.
Because they can improve their communication skills.
Because they can build a portfolio.
Because they can refer to it in many places.
Because they can have hyperlinks.
Because they can maintain a website.
Because they can.