I found this article on broadcasters and responders with regards to twitter, and I think their suggestion hold true of blogging, as well as micro/nano blogs like twitter.
Broadcasters Have something to say, and want you to hear it. Or they assume you are hearing it.
Responders Like to follow others, reply to them and comment, and repost, and link, and retweet. They enjoy sharing other people's stuff and interacting with it.
Now Broadcasters think responders are people they don't have time to waste on. They won't reply to your comments, but are happy for you to play on the sandbox of the comment space of their blog as sycophantically as you want.
And if you send them a message in response to a tweet, they would never dain to reply to you there either. They expect large numbers of followers on twitter, and as a de facto sign of being a broadcaster, ensure the number of people they follow is low. After all they have much more important things to do like broadcast to the unwashed masses.
Then responders don't understand why Broadcasters don't reply to their comments, or their direct tweets. But in the hope that the Almighty broadcaster will one day notice them, they vainly continue to comment and re-tweet.
Aside from the tongue in cheek with the above, I do have my process for blog following and tweeters.
1. Essential Broadcasters: There are some blogs I follow and twitter people, for their content. I don't comment, or interact, and I read them for the superb content they provide. Once in a while I'll say thanks.
I don't need or want them to reply. I like them more if they have closed comments. Len Sweet, is the best tweeter I follow, and he'll probably never reply to most people, but he has stuff I want to hear (but I also hope he notices me, pick me Len, pick me... :-)
2. Other Broadcasters: If I'm reading other broadcasters it's because I'm looking for people to interact with. If I see they never reply to comments, it feels a little sycophantic and I'll take my interactions to people who want to interact.
Then if anyone is rude, polarizing and divisive, I'll give them a miss.
My blog & twitter I guess I think I have something to say, but want to interact with others, and will reply to comments. I enjoy the interactions and learn from them. And if you message me about something I tweeted, I'll at least say thanks. That's just polite isn't it?
Inane Blogs and Tweets I don't need to know about someones latest post-modern dinner experience, or that they just woke up, then went to the toilet, then made coffee, then opened the post, then fed the dog etc etc.
Having said that some friends, and even some people I don't know post inane stuff in an interesting way, and I enjoy following them.
Conclusion I think I filter facebook, and update comments, and wall to wall messages in the same way. I'm a mixture of broadcaster who likes to respond. How about you?