How do they do it?

I like to read P.Z. Meyer's blog Pharyngula, mostly for the religion bashing but also for the scientific information and discussion I wouldn't get in my real life. He has a lot of posters and probably 300 times as many readers. I'm supremely jealous.

Is it bad form to poach topics? I don't imagine that writing about the same things he does is plagiarism, it's nothing like taking what he's written and passing it on as my own, I'd just be commenting on some of his immensely interesting articles and observations. It'll help me write more often, because I'm doing a bad job of staying motivated.