Some people prefer to publish a network of blogs instead of merely focusing on a single blog. This strategy sometimes works and sometimes it doesn’t work, actually it depends upon the kind of resources and time you have. Starting a blog network requires lots of money and time because it cannot be achieved single-handedly. Writing for more than one blog can take up lots of time and it is very hard to concentrate on different topics. Besides, you’re not only generating content for your blog you are also constantly marketing it and promoting it.
Unless you have lots of resources it is not advised to start multiple blogs. Start with a single blog, put all your energies into it and make it into a successful entity. Once this blog has started drawing decent traffic and some income you can use this blog to launch another blog. Usually, as it happens with every sphere of life, one success leads to another.
Darren on his blog explains how to start a network of blogs.