Around the time that newzbin went down, a few people were discussing the pain of having written apps which interact with the big usenet indexers via apis, only for the site to go down and the work be wasted. Whilst there was a couple of notable GPLd indexing sites like Ikbin and URD, a couple of people decided to go about writing a new usenet index site, with community features which would have a similar effect that tbsource did to torrenting sites. Something that could be fairly easily installed on a home NAS or web server, churn out nzbs in a user friendly format and work directly with sabnzbd, creating a slick way to find and request usenet content from one interface.
As nzbs.org is the best nzb site on the web :-), we took as many of its features, clean interface and all round goodness and tried to roll it into an application called newznab.
Now newznab is getting fairly stable, it seemed like a good idea to tell a few people about it.
The technology stack is PHP/Smarty application, a mysql database with gzipped nzb files and a simple web based search interface onto the data. It is supported natively by Sickbeard, CouchPotato and Newsflash+ via a pretty comprehensive api
Our irc presence is on irc.synirc.net #newznab
good work! 
But I've a problem updating the groups...
) Perhaps I don't understand the configuration.