[TL;DR - Uploading NCS music is a violation of both the Terms of Service for Newgrounds as well as the terms of license for No Copyright Sound. Uploading NCS music to Newgrounds, credited or otherwise, WILL result in removal of the offending media and a ban at staff discretion.]
There seems to be a lot of confusion about NCS: what it is, what the title means, and how licensing works. The confusion stems from the name of the label (and it is a label) which people assume means you can just post it willy nilly with no consequence.
WHAT IT IS:
No Copyright Sounds is a UK-based music label which signs independent artists. Those artists are paid for their work by NCS, which in turn licenses the music royalty free for use on/in YouTube and Twitch content.
Their official mission statement is as follows:
NCS is a Record Label dedicated to giving a platform to the next generation of Artists in Electronic Music, representing genres from House to Dubstep via Trap, Drum & Bass, Electro Pop and more.
NCS makes its full catalogue available to Creators for use in their YouTube & Twitch content safe from infringement, with every NCS release available as a free download. - If you're a brand or a commercial organisation interested in using NCS music, please get in touch at firstname.lastname@example.org
There are a large number of signed artists under the NCS label, with some coming and going as their contracts terminate. Wikipedia has a nice list of these signed artists.
WHAT IT ISN'T:
A song released under NCS branded channels are not available to be publically posted by end users. The end user is allowed, following the license agreement, to USE music licensed under NCS in videos they create on YouTube, or to play on a Twitch stream without copyright strikes against their channel. Licensing outside of YouTube and Twitch requires a specific license agreement, to be made with NCS. The music still has to be properly credited in the following format:
Full title of the track
Link to the track (NCS YouTube)
Credit to artists via their social media links
NCS music is only allowed on YouTube and Twitch, because NCS has arranged a license agreement which avoids copyright strikes. NCS does NOT have this relationship on other sites. They have stated that while you could in theory use music from an NCS signed artist on Facebook/Instagram/etc, you will likely receive a copyright strike which could terminate your account.
By the same terms, they state that you CANNOT use NCS signed music in games, movies, or anything monetized as it counts as commercial use and requires a direct license with NCS and the user. This ensures that NCS and the Artist gets a fair share of the monetization for the service they provide.
WHY THIS MATTERS:
Newgrounds is an independent website, not owned by a large corporation. The audio portal has been around for over a decade, allowing aspiring independent artists to create and submit music shared within the community. The audio portal gives these artists exposure, and allows other content creators (who make games and movies for Newgrounds) a place to find music under a Creative Commons license.
Here endeth the lesson.