I really strongly dislike (not quite hate) the way that Internet.com supports their mailing lists.
Dear WebReference Update Subscriber,
You are receiving this e-mail from WebReference Update and
internet.com as part of your subscription to WebReference Update
Instead of simply putting in ads with their regular content (which they also do) they also
send out extra email messages with no valid content, just the ad! Luckily these are easily filtered out, but it is still rather annoying.