The world wide web (or web for short) is a good place for you to keep a log of you're activities. It's lets people see who you are, what you do and why you're doing it. If you're so inclined, you also invite comments on what you share.
What you post to your web log (or blog for short) is entirely up to you. The things you post on your blog (a.k.a. blog posts) can take any format you like. A popular one is to post a note of what happened in your week. These week notes have many styles, some of which you can see on Sam Villis's blog post on Week note styles.
My week notes journey
I want to stabilise my on / off relationship with week notes. I range from blogging every weekday to going months without a single post. Rather than setting another new year's resolution, I've made it my intention to publish a week note every week.
I'm a member of the weeknot.es community which is hosted on Medium.com (a popular blogging platform). I sometimes see other members posts popup in my Twitter feed. I draw inspiration and encouragement from this community to help me blog better.