It's been said that "every system evolves until it uses email." While this isn't always true, and email is quite unpopular with some people, others prefer it over alternative information delivery methods.
Those who prefer email updates can now subscribe to the Depth-First feed via email. Whenever a new article is posted, you'll receive an email containing the full text as HTML. I accomplished this feat without so much as writing a line of code by taking advantage of FeedBurner Email. I "discovered" this feature after reading about Antony Williams' use of it on his blog.
You can find a permanent link to the email subscription form on Depth-First's right-hand sidebar under "Feed":