i dont know i signed up and i had no idea what I was signing up for , thenafter i seen my control panle, and stuff, and i still had no idea what the h*** the site was all about ,it gives u a website/page i think , but i havent seen my one yet lol.. sign up and see if you can find out what it is
I have seen it a lot too but never really looked into it. If you care to share what it is about should you discover the answer I would be more than happy to read about it.
Postnuke is built on PHP and IMO is sort of a glorified forums; PHPnuke is a another similar one. They are kind of like prebuilt sites that you add the content and decide on the colors and images. Great way for an beginning/intermediate webmaster to look like they are advanced--of course, there are other ways to do this.
postnuke was actually developed from phpnuke - but the developers took postnuke in a different direction
i used it for a month there and it can be set up very quickly and can be very easy to administer
my unitred site uses a portal which is a derivative of postnuke
its a good piece of software thought the support is non existent and you have to figure out a lot of it yourself