Over the past 12-18 months Nintendo has had a rocky relationship with YouTube and its creators — in mid-2013 the company aggressively claimed revenues on videos including its content (such as Let's Plays etc) and was heavily criticised by some YouTubers, commentators and consumers; it then backed off substantially later in 2013 and ever since, showing greater leniency.
Earlier this year Nintendo of Japan addressed the ongoing issue by stating that it was starting to tag videos with this content, but also that it would implement an affiliate program on YouTube to formalise deals for revenue sharing and permitted use of its copyright material. It's a sticky topic, as while Nintendo has a right to claim revenues earned through the broadcasting of its copyrighted material, many major companies simply leave content creators to their own devices — all in the interest of what can be, through these popular videos, free advertising and exposure for games.
It seems Nintendo is still ticking along while identifying its next move, with no major announcement on this affiliate program as yet. Some interesting news has come out of Japan, however, as Nintendo has confirmed its participation in the "Creative Endorsement Program" for popular Japanese video service NicoNico, in which Nintendo owns some shares. The company has listed 250 applicable games so far that can be featured in content such as Let's Play videos, for example, while also showing no objection to 'derivative works' such as fan art, music videos and so on. Content creators that produce the most popular videos will be rewarded by the endorsement program, so structurally this isn't that far off the previously announced plans for YouTube.
To address one area around 'derivative works', some have attributed this to give free rein to ROM hacks and fan-made games. The source article doesn't suggest this, as far as we can see, and the mention of derivative content is in the context of videos, with examples given such as those we've listed above. Regardless of that, Nintendo often leaves these fan games alone — as the many freely available Mario clones available on PC attest, in addition to examples such as Project M — and seems to only step in when profit is being sought on its copyrighted material. This announcement doesn't seem to change that status quo.
In terms of YouTube, it'll be interesting to see whether this niconico announcement paves the way for a formal setup on the Google-owned service, or indeed whether Nintendo will quietly step away — like other publishers have done — to leave content creators well alone. Time will tell.