I'd say it's the bases you see people posting. Miscreants the world over use them without giving credit to the maker.
But recently, has been hit with a bevy of street rats who steal her speedpaints and pass them off as their own (but never copy and paste her descriptions for the videos, they don't have the time!). It seems she's had experience with video thieves before...
Here is something of mine that was the most used, but I never seen where someone made a copy of it. I think the lighting trail made it unique, and not easy to copy that effect. I have made a few of my own to remake it, and it didn't look quite the same.
It was used straight from my website with an image link to help sell DVDs on ebay. I changed the name and the location of the file, but I was still getting a lot of traffic using bandwidth I had to pay for just for the link to my website even when it didn't find anything.
While I was here I have seen a lot of pictures of eyes, and people remaking the spray can idea to look like someone was spray painting the clouds in the sky.
I think when it comes to ideas, people like to take credit for being creative, when it was not their idea.
I see face book have everything to make a heart shape, from an open book with a ring to make the shadow of a heart to people doing it with their fingers as if that shape is supposed to mean something like love, but used to much to mean anything but a sign for copy cat. The over use make it fit in it's own category for just heart shapes and people think this figure is not seen enough, because it don't mean love, it is just a heart.
An American Indian said the the two finger held up to mean peace is the sign Indians used for wolf, so they thought it was strange when everything was making the sign of the wolf. It is like the boy who cried wolf. When you hear it and it means nothing then you stop listening. The repeated ideas, is just something we should avoid looking at, because we saw them enough. People think by doing this get them attention, but it is the attention to know what to avoid.
Good ideas might help people get attention, but it is a one time thing that don't last, and the best ideas comes from knowing a lot of things you see differently than anyone else. When everyone is doing it, then it don't mean anything.