Okay, first things first. I cannot alter the default setting myself. I looked for ways. I even tried a couple creative ways, like altering the CSS code. Doesn't work. This is a setting you have to change yourself. Thankfully it's easy.
1. Up near the top there's a row of links: Home, FAQ, Search etc. Among them is "Profile"; click on that.
2. In your profile, near the top, there's another row, with "Information," first, then "Preferences". Go to the Preferences.
3. The sixth item from the top is "Always notify me of replies;" change this to "No."
There you go. Now the emails will stop. Once more, I cannot change this default setting; you have to do it.