I am fortunate to have many talented writer friends. Most of them are much more accomplished and successful than I am. That's why I'm always surprised when I ask about their blog and they say they don't have one.
There's no rule that all writers must have a blog, of course. I'm sure the ones who are the most successful are too busy writing for money, not personal notoriety like yours truly. But even if you don't think you "need" a blog as a writer, there are many good reasons you should consider one.
1. People want to get to know the real you. If you're writing medical articles all day long you're probably not getting to inject a lot of your own voice in your pieces. What's going on in your head when you're not querying and writing and editing? What are your passions? What ticks you off? Being your honest, true self is often scary. I sometimes wish I could delete a post I've written, because it shows vulnerability or a strange inclination to sing to cats. But the Internet is full of phonies. Be authentic, and I do believe fame and fortune will follow. Eventually.
2. You have something to say, even if you don't know it yet. I have been struggling to come up with good article ideas since getting laid off last year. It's hard to think of something original when the only other beings you come into contact with all day are four unimpressed cats. But blogging should be no-pressure writing. Just say it, even if it's silly or weird or controversial or kind of boring. I fight with this every day, as I think I should only blog when I have something earth shattering to say. The funny thing is, quantity will eventually produce some quality when you blog. The more you blog, the more chances you have to say something that catches the eye of readers.
3. Try something new. If you're primarily writing straightforward articles, look at your blog as a chance to break out. Write poetry. Post your amateur photos with witty captions. Write a blog as your pet. Post an experiment, such as making something every day or reading and reviewing a book every week. Julie Powell did this and turned her blog into Julie and Julia. Who says you can't have the next big blog thing? If nothing else, the creative muscle stretching will make your writing richer.
4. Show off your expertise. Let's say you are excellent at knitting with cat hair. When you're sending in a query or emailing a potential client, it's simple to say, "I've been blogging about knitting with cat hair for two years" and give links to pertinent blog posts you've researched and written. Ta da, you're an expert. The blogosphere is full of general blogs with inane babbling, like the one you're reading, but the specialty blogs are where it's at. If you're really good at something, a blog is the place to let your little light shine.
If you're reading this and finally decide to create a special blog of your very own, come back and tell me about it in the comments. Or if you are a writer and think I'm full of crap, share that, too.