I read recently that 175,000 blogs are begun each day. I'm not sure that high number tells the whole story.
I suspect that the more nearly accurate statement is that 175,000 blog accounts are opened each day. I recall opening several -- 3? 4? 6? -- when I'd happen upon blog postings that I wanted to comment on and could only do so if I opened an account. So I entered information, up to and including a blog name invented on the spot, posted my comment, and went on with my life. This was in the early days of blogging, and my sign-up was a casual act. Perhaps I scribbled down the names of those blogs, and perhaps some day the pieces of paper on which I scribbled them will surface. Whether I ever return to them, or post on them, or not, those unused blogs are counted in the total figures. So are all of the blogs that people begin, post to twice, and never return to. I'm not saying there aren't a lot of blogs. I'm just saying that there may not be as many as the numbers lead you to believe.