Jeff Jarvis is arguing with Jakob Nielsen over comments Nielson made in support of e-mail newsletters.

Jarvis writes:

… Nielsen sticks to his guns pushing email newsletters (I haven’t subscribed to once since about 2002, myself and not being able to get rid of half of them that I no longer read I now mark them as spam and never open them) over these newfangled RSS feeds and blogs …

Nielsen responds that Jarvis arguments are invalid because they are based on personal experience and not data. Of course, Nielsen doesn’t offer any data either.

Here’s a real simple test for a site with both newsletters and RSS — how many people subscribe to feeds vs. newsletters? I currently don’t have access to those numbers, but I’ll bet bytes to buffers that newsletters remain more popular than RSS feeds at most general-interest sites.

To put it in usability terms, I go back again to “Don’t Make Me Think.” RSS makes users think. E-mail doesn’t. RSS may one day over take e-mail, but so far the adoption rate seems pretty damn slow. For the average user, e-mail remains so much easier to understand.

Other than that, Nielsen’s site in inexplicably ugly and hard to use. Jarvis and I agree on that much, at least.

UPDATE: Jay Small has his say.

Something I forgot to mention: For newsletters, number of subscribers isn’t a reasonable metric, even if you’re daily deleting bad addresses. The only meaningful measurement is open rates. For RSS, the best thing to track is downloads. If you’re using a measurement tool like Omniture, this becomes problematic, as far as I understand how Omniture works — it measures downloads based on clicks from pages with the Omniture tags installed. That means downloads via an RSS reader (or for video and audio, downloads by direct links from other sites, e-mail or IM) are not measured. To measure these downloads (not necessarily with 100 percent accuracy) you need a good old fashioned serve log analyzer.

Every news site should have both e-mail newsletters and RSS, and should be tracking both closely. If RSS really is the superior technology, it will eventually overtake e-mail, at which time sites can safely abandon e-mail newsletters.

I should also mention, I get a couple of e-mail newsletters — my favorites are on gardening from Home Depot and HGTV. They work for me, in part, because I use Gmail, which has a great spam filter. The point is: Spam hasn’t necessarily killed e-mail yet, and as Spam filters improve, the better for e-mail newsletters.