I like to think there's some kind of idea-well from which we all draw. They don't belong to us, as individuals – we just happen to have tapped into something universal. In that sense, sharing makes sense...to me, at least.
How many times have you had an awesome idea, only to see that very thing pop up online, seemingly originating in some far off, distant land? Happens all the time.
Oh yes, I've thought about this too... What if Ideas are alive? like they exist... and if you don't hold on to it, they simply move on to the next head...
Crazy thought, but its in my head at times.