You got a lot of comments here...I hesitate to add to it :))
I usually only comment when I have something to say. Sometimes I do comment to a 'friend', but then it's again as you say, we have a relationship (online) and a few words do it.
My blogging and my comments come from the same well: If something genuinely interests me, I'll write something. Otherwise, I'm wasting the blogger's time and my time.
Good post. I hope newbies especially read it.
Thank you! I hope they read it as well. I think it's pretty sound advice even if you tweak it a little bit. I'm probably the same, I don't really comment on stuff that doesn't look interesting unless I have a prior relationship with the person.