I remember what happened… and why I did what I did.
Pardon my rather lame quotation of myself from the comments:
This is NOT on the Dashboard page, but the “Read Blogs” tab from the WordPress main page, and then “Manage Delivery Settings” at the bottom of the list. I unchecked “Block all email updates from blogs you’re following on WordPress.com”– I may have gotten overzealous as I don’t want e-mails on every new blog post (I have a feed reader, as I said, for that).
Well, more specifically, I’m following my own blogs. I think that happened because I wanted to be informed of when Cimmy added things to the Journal Jar (that blog needs some lovin’, by the way, not to mention we need to post to it again). I got annoyed and starting blocking updates. However, it was a sledgehammer approach and blocked comment updates from blogs other than my own.