Passion for Success notes an interesting beneficial side-effect from blogging:
"Ever since I started blogging... (well i am into my 2nd week).. I realised I am no longer just a participant in life, but a keen observer of life, I watch and listen to normal day to day happenings and wonder if it would be an interesting topic for my blog.... "
This "zen of blogging" effect I think much better explains the explosion of blogs than the "slashdot" or "scobleized" effects. Some people only THINK they want to be famous. What keeps them blogging is the self-knowledge they arrive at through the reflection required for the blog, or the satisfaction derived from helping others.
Comments and feedback really DO matter for this use case. The little canaries miners used to carry with them "down t'mine" to warn them of air quality issues kept at their jobs because of the daily care and feeding the miners gave, not because of the early-warning mission.
If you care about the blogs you read, leave comments. Keep them fed and alert and motivated.