What Makes for a Good Blog?
I think of deciding “good” for a blog as being the same as for most anything else. In effect, blogs must attract customers. "Good" would be based on the same kind of consumer reasoning that goes into repeat purchases of a commercial item or repeat visits to a business.
Referrals would be a good indicator as well. Word-of-mouth, or mentions in other places, whether on the Internet, in other media, or from people. Links on blogrolls would be another – a link is a vote of confidence.