Tyler, you kick ass. From the way you build up to the numbers, you seem almost apologetic for your app's success. You don't have to apologize for making money on software, even if it is unfashionable.
I think you're able to charge $49 where an RSS reader can't because your audience is more professional. I'm one of thousands of other webmasters who have ...started GUI frontends for Apache, so I know what this is worth. Now, you going to add support for Nginx? :)