While all four C’s are powerful and valuable, note the third suggestion under “Content”
“Serve: Make no mistake. You are in the service industry. If your content offers no value – neither do you.”
A good mission statement for your blog should include verbiage to that effect, and you should judge every post by that dictum.
Here’s something else to remember: entries in your blog won’t disappear like yesterday’s newspaper. Keep in mind that search engines will hit your entries as long as they’re posted. If that’s not humbling, I don’t know what is.