How do you know your blog is useful?

On July 31, 2006, Technorati tracked its 50 millionth blog.
(http://www.sifry.com/alerts/archives/000436.html)

Has blogging reached its point of saturation and implies decreasing returns from here on out?
Will only those blogs which stir the reader into an action survive?

However, not all blogs allow for reader comments. The debate over comments on blogs is as old
as blogging — the meme recently resurfaced when Zoli Erdos declared that The Official Google
Blog is not a blog because it doesn’t allow comments.
(http://www.blogherald.com/2007/01/03/the-great-comment-debate-who-really-cares-what-you-think/)

How then is a blogger to guage the utility of his or her blog?

One way would be as used by Rich DeMuro of CNET TV on Dec.21, 2006 -

Get a free Craigsnumber, set it to expire in an hour (or day), and share it with your viewers/readers. The number of callers will indicate the utility of the blog or show shared.

The added anonymity provided by Craigsnumber, and the simplicity of obtaining one are gravy!

If the age-old notion of "user feedback" enabled by Craigsnumber in this case appeals to you,

Call me at: (415) 632 1256 x 405 (my craigsnumber)

Happy blogging!