I don't use social media, so if people search for me, they can find my website.
Blog: To ventilate and network.
My blog posts have landed me job interviews and have expanded my professional network.
But I mostly blog because I write a lot. I write to myself, and sometimes I think it's valuable to others, and then I have a place where I can share that and link to it. For example, when my colleagues make sketchy code, and I can't find a good place that explains why you want to think about it differently, I'll write a blog post.