When you sign up for this thing, which I only did to help connect with people in my own market niche, I was FORCED to choose ten "hubs" in order to get started. I looked at all the hubs and I have ZERO.000 interest in ANY of them but now I'm getting daily emails about subjects I could not possibly care less about. I know, I know: change my email preferences. But is there NO way to use Hubpages without feigning interest in all those categories to use the site?
I am not entirely sure which mailing you are referring to, but you can unsubscribe from any/all of them. I suggest looking at the various mailings and subscribing to the ones that interest you or use "following" instead to focus on particular hubbers.