Your existing blog looks quite good. Keeping one blog with multiple categories is always good as that will bring more traffic in future and popularity of your blog will improve with traffic. maintaining separate blogs is like maintaining separate websites and managing all those websites.
! blog is good to focus on and maintain it.
I tend to agree with Webhostinguk, with the flexibility of sub categories, and the many tagging options out there, you could do just one blog.
You may also want to look at this plugin
http://tools.webguerrilla.com/wordpress-subdomain-plugin/
It should allow you to install a single copy of WP, and each category is then, http://www.category.yourdomain.com, giving the impression of different blogs, though I’ve not personally tested it.
My company is preparing to launch a new product called Travel Safety Net. It’s a roadside assistance program like AAA. I’m exploring the feasability of a blog to support the product and to draw visitors to our website.
This is a simple product about which there’s really not that much to say. So our blog must be about something more substantial, yet related. We want a travel-related blog, but not your standard travelogue. So my idea is a blog called “Bands on the Road” with the outrageous tales and adventures of traveling musicians.
To get it started I would post my own stories and I would seek out guest contributors to post their stories on our blog, as well.
Our logo and our ad would appear on the right side of the page, with any special messages we want to deliver. And of course that would link to our website. Bands on the Road would be officially sponsored by Travel safety Net.
These are bound to be fascinating stories and I think this would generate a lot of buzz and attract a lot music fans, young and old. With traffic coming to the Blog site we’re bound to have a few clicks on our Travelers Safety Net logo for more information.
What do you think?
