No, you don't have to share your identity on a blog. You can choose to remain anonymous if you prefer. However, it is essential to remember that creating an online presence with a unique identity can help people take you more seriously and build trust in your content. That said, starting an anonymous blog is a perfectly valid option if you prefer. As long as your content is interesting, informative, and engaging, your readers won't necessarily need to know who you are to enjoy your blog.