Right answer is the most obvious one. Learning. Blogging helps a lot when you are obsessed with learning and creating new things.
You learn a lot if you blog responsibly
I started my first blog in 2011 (I run two now). It was first time I got an Internet connection of my own. I was excited and I did some posts about few things I was trying those days. Some people read it, few praised it, it felt nice. Then I got bored. And I stopped writing slowly. There were people thanking me for putting my time in writing and encouraging me to write more. But I couldn't.
I was not doing it right. I am a geek, not a blogger or writer or poet (although I blog and write poems). Actually I recently discovered it. Writing and blogging become all so much fun when you stop writing what you already know. Sharing experience is cool. Actually it is only the experience that is worth writing about. But for me it was very boring to sit down and write about what I already knew. Then I tried writing posts as notes. Notes to remind me how to do stuff I know I will forget in some time. But it didn't work either.
And then I started blogging with a different objective. Earlier I was writing my experience to help people. But (un?)fortunately I am not that good a person who would do things for helping others and enjoy it. I am little more on the devil's side.
For about few weeks now, I am blogging for learning. Instead of writing a post I already know, I write about things I want to know. I choose a topic (say git), and think of a post I want to read about it (say, how internals of .git directory work?). Then I start preparing to write it.
No I don't Google it. It might be already written. There might be 10 posts already crawling through reddit on the same topic. I don't give a fuck. What you read in blog posts is the summary. It's the juice drawn from sugarcane. But the real thing a geek want is knowledge. True knowledge can only be acquired by experience. You have to live through the process of putting a piece down in soil, and grow your experience into the sugarcane from which you can draw the juice and put in your post. Of course how much you learn depends all on how much work you can put when writing a post. I found it particularly beneficial to write about topics I have some experience in but want to go deeper. Like git. I use it everyday, but digging deeper is not a requirement.
In my opinion, the secret sauce which make this work is responsibility. When you write a post and you know people gonna read it, you can't write carelessly. I can't say about others, but I feel a sense of responsibility when I am writing about something I haven't personally experienced long enough. It make me work extra hard.
"Great power brings great responsibility", right? The inverse is also true (in this case at least). Great responsibility can bring great power as well (provided you can feel it). This worked with me. It might work with you as well (unless you have already surpassed me in terms of slacking and procrastination).