What happened was this:
I installed the cocomment Firefox extension. While on flickr I sent a flickrmail to someone. I didn't turn off comments, so cocomment tracked mine. I have an RSS feed to comments similar to mine, so anyone else with the same extension who sent an email from flickr (flickrmail) showed up in my feed reader:
Something to be aware of. Although it's tempting to read those emails, I haven't.