One of the main objections I hear from people when I encourage them to start a blog is - 'Well I would start one, but what would I say?'
These are often senior people with a good grasp of their industry and specific knowledge of what is going on in their market. Credible, experienced, articulate professionals who have no problem entertaining and educating you on a one-to-one basis.
They certainly don't lack the content. I think the subtext here is more - 'Well I would start one, but who would be interested in what I'd say?'
Most successful marketers that I have met, and indeed most successful entrepreneurs and business people in general, are fairly insecure. They fear failure, and so push themselves twice as hard as their more assured counterparts to make damn sure they succeed. (Interestingly and paradoxically these same people also embrace and learn a lot from failure when it does come aknocking.)
One of the things though about blogging is that no-one need know how many people are listening, if you don't want them to. You can have the party without the fear that no-one will come. This is good since at first you will be your only reader, the only one at the party. But gradually others will come and join in. That's where the conversation begins and you start engaging.
It's easy to become obsessed with gaining more traffic, more readers. Just look at how many guides there are to building traffic. Sure there are some basic rules - you post more often, you have more content for your audience etc, etc.
But while the amount of traffic is a reasonable quantitative measure, it shouldn't become the goal or a reason not to start in the first place. Just trying to win new readers can defeat a higher goal of communicating with those you have, of interacting and learning from them. For instance, I like to spend time meeting people who kindly read my blog. For me that's one of the most valuable and fruitful parts of the medium - it has nothing to do with traffic stats.
So to circle back to my point, I don't think you need worry about who will read your fledgling blog. If you say what you believe and know, your readers will find you and love/hate you for it. Don't worry how many you have. It's bound to be more than if you didn't blog at all, and if you keep at it, the numbers will grow.
By the same token, when I go running, I sometimes leave my watch behind and just run as fast and as far as I like. It helps me to focus on the sport, not the numbers. It might not be a personal best but it's still satisfying. I think sometimes the same is true for blogging. Don't be put off by marathon runners, or A-listers - you don't have to aim to be Paula Radcliffe or Robert Scoble. Just yourself.