Fever is a download-and-install Web-based feed reader that has a "what's hot" twist. Keeping up with a lot of feed subscriptions is a challenge and so Shaun has created a process that looks at the popularity of the topic being written about and gives you the ability to sort things to catch up with "What's hot" right now quickly. He seems to keep referring to it as a local-Digg, though it is more like a local-Trending. Fever is also a full featured feed reader so if you just want to sit down with a cup of coffee and read your friend's blogs - you can do that too.
I love the idea. I am not sure exactly what Fever is doing to enable the Fever-hot list, but I suppose that is the secret sauce of this entire thing, but if it works well then he's got a hot ticket on his hands here. I'm looking forward to one day giving it a spin. The demo video on the site is wholly impressive.
The only gripe I have is that in a world of Web services, which I'm getting more and more in love with over time, Fever is a PHP/MySQL download and install type application. Some may love this, some may not. The installation looks a little tough for the average user. If Shaun partnered with someone to make this a Web service that he could charge for, (and he's usually partnered with our mutual friends at Media Temple for stuff like this), I think this would have been a much bigger deal and had a broader audience.
That being said, he has a user base of Mint customers that he can sell against. If you can download and install Mint, you can download and install Fever, and that might be more than enough for Shaun to call Fever a huge success.