My Blogging Self-Evaluation: Why This Blog Should Only Focus on One Niche

This thought came up right after I read Darren Rowse's post about the benefits of building a more focused blog. By 'a more focused blog', I mean a blog that has more a specific niche (a position particularly well suited to the person who occupies it- Wordweb dictionary). Darren wrote that he at the first time and a lot of other newbies wrote their first blog with topics ranging from topic A to topic Z. This would be very easy to start with because we simply have endless supply of topics to talk about. We can write a post almost every day,  even  several posts a day, hoping to attract more readers, search engines and bucks!