According to comScore Media Metrix, it looks like Howard Stern hasn't lost his edge in terms of traffic even after moving over to SIRIUS Satellite Radio. His site even beats out Rush Limbaugh.
Here's the comScore chart showing a year's worth of traffic details:
Interestingly enough, these don't correlate with Alexa's traffic numbers, here's Howard Stern vs Rush Limbaugh's Alexa numbers:
Now, of course statistics are only as good as the data they're derived from - so it can be argued that more "adware friendly" people will visit Rush's website and thus are more likely to skew the numbers for Alexa. But more than anything, I'd look at these charts in terms of trending. Don't look at the hard numbers (and be wary of them), but instead compare the two in terms of the peaks and valleys. Comscore doesn't seem to be registering the spikes on Dec 16th, 2005 and on Jan 9th, 2006 - so I'd assume they're doing a rolling average of some sort.
Either way, it's neat stuff to look at and to help decide whether the "Long Tail" of Howard actually exists or not. Read more on The Back of the Napkin.
Speaking of Long Tail, there's a free, anonynous survey targeted to Howard Stern fans to help determine whether the Stern Effect was actually limited to Dec-Jan. It's completely free and anonymous - so go fill it out here.
Howard Stern still has a radio show?