I seriously doesn't know how NU works. (-_-) Does NU have a group about Oiriginal Novel Authors or can Original Novel Authors/Writers can have a group in NU? I really don't know.
Original authors/writers can put their creations here: http://forum.novelupdates.com/forums/community-fictions.1016/ There is a group of writers on NUF already: http://forum.novelupdates.com/threads/monthly-short-story-writing-prompts.19466/ That's pretty much all I can think of. As for how NU works, try reading the first post of these: http://forum.novelupdates.com/threads/reading-list-tutorial.3120/ and http://forum.novelupdates.com/threads/how-does-novel-updates-work.21477/
Yeah Tony has said at somepoint he will create an indexing aggregator for English Original Webnovels. It's probably still a long way off unfortunately.