I'm not into people directly using the exact files I create myself (I mean, do your own work). But I don't think anybody owns the idea of "three cogs", "a newspaper that curls to the left", or "a head with a speech bubble". Don't get me started on things like Coke owning a particular part of the red light spectrum... Value comes from solving problems, not from a font, or a colour, or a texture, or a style.
EDIT: When I say i'm not into it, I don't mean I mind people using things I've made as building blocks for their own creations. I just think if you're going to use something, make something new/better out of it.
I'm repulsed at the idea of "owning" a visual depiction of a fucking newspaper.
And yes, I've worked for years of my life as a designer. I know what if feels like to have people copy you.