I watched a Brandon Sanderson video where a former student spoke to the class. She told how she got an agent. Brandon was surprised how fast it happened for her. The girl noted she started getting visits to her blog site from major publishing house addresses. She called her agent and wondered what was happening. She learned the publishers wanted to know of the professionalism of the author, and they did that through her blog. They wanted to know if she was professional and marketable, and she was.

It is well worth having some kind of social-media presence, even if your blog is not populated. You demonstrate professionalism, knowledge, your interests, friends, and so forth.