You call me as something physical, something you can touch.
But to be technically correct, I don't weight very much.
In fact, my weight is zero, I'm not of matter at all.
Yet, I can cause damage, inflicting material fall.
My creation involved once upon a time a feather.
But I'm said to be a spawn of curiosity and weather.
I'm opposed to an animal but I can spread like a disease.
If I'm plenty you'll nag, if I'm scarce you'll feel an unease.
Some people haven't yet seen me, others see me all day.
Sometimes I'm kept securely, sometimes thrown away.
What am I?
Apparently, the question caused a lot of headache for the community (as it should), so there's the natural suspicion that it might be poorly formulated. I understand that and I promise that I've taken a lot of consideration to make sure it isn't. Please view the other question of mine for verification.
Nevertheless, I'll collect the pointers and comments below to improve the solving experience. I hope it helps the community to reopen it.
refers to the old style writing equipment.
Curiosity and weather...
refers to Bejamin Franklin's interest for electricity.
Feather vs. curiosity and weather...
need to be viewed together as a polarity.
is an actual, real species existing today, commonly spread over most areas of the world.
Opposed to an animal...
refers to the term used to describe the opposite of our subject. If we would be looking for recession (i.e. bear market), the opposite animal would be bull. Remember, the subject is described without the animal epithet - its original version is, however.
Spreading like a disease...
refers to the rapid rate of spread but also the way, or rather nature, of the spread.
Nagging vs being uneasy...
refers to different qualities of the subjects, as the few appreciated ones are welcome, while the most of them aren't. It's possible to be displeased of the excessive number of such and simultaneously happy about the few that are wanted.
People who hasn't seen it...
are real people living today, although it's more and more unlikely to find such individuals. In fact, in the contemporary world, only remote tribes, extremely secluded communities and special cases as gravely handicapped, mentally challenged, infants and some of the elders may not be aware of the subject.
refers both to the nature of the spread and to the period of storage.
refers to disposing of the unwanted or already consumed subjects.
What am I?
On average, I'd say that it's a very common concept used by you on daily basing, spoken of frequently and relied on since many years. It can be described by a single word or a few (all in all less than five, without disclosing the exact number).