Email and RSS are different things. I know that email lists are the cool thing in online marketing at the moment. But wouldn't you rather have people interested in you seeking out what you have to say rather than just hitting the Archive button because they don't have time to read your email right now? That's what RSS is, people actively asking you what you have to say on a regular basis.
If you're worried that you need to know who all those people are (which I get is a legitimate marketing benefit to an email list), have your geeks through an identifier into the url's query string and give each of us our own rss feed (for example, I think http://arstechnica.com does this for subscribers). But please please please, don't get rid of the RSS feeds. I get too much email as it is. I get your emails, and I pay much less attention than I do to the RSS feed.
Besides, its good for your open source roots.