Re-publishing Videos

[bsteve]

I see a plenty of people do this. They download other people's videos change its style into their own and republish it in the video for share and likes. Is this a really good idea? I mean there should be some rules and regulations regarding this.

While re-publishing they just mention the original poster as their source or just put a link back in it. Social media channels are good in getting things viral but is this not breaking any rules?