A lot of rumors are the result of poor understanding or misinterpretation. For example, there was a big rumor a year or two back that the US government was buying hundreds of millions of rounds of ammunition, sparking fears of everything from a conspiracy to drive up prices to an imminent imposition of martial law. The basis of the rumor was a government solicitation to bid on ammunition pricing, so that the government could lock in its ammunition purchases for the next few years at a fixed and predictable price, rather than being subject to spot price fluctuations which would make budgeting more difficult and possibly result in higher costs. However, to understand that that the government was looking for (essentially) a call option required a basic knowledge of finance and a fairly high level of reading ability to deal with the 'officialese'. It's not surprising that many people misinterpreted a request for a pricing guarantee as a solicitation for actual supply. There was also a misunderstanding of how much ammunition the government actually uses, with people who cheerfully fire off hundreds of rounds during their own practice sessions overlooking the fact that federal employees who carry firearms also have to take part in training and practice sessions where they expend large quantities of ammunition. More here: http://www.snopes.com/politics/guns/ssabullets.asp
Trolls shouldn't need much explanation; a tradition of spreading outlandish or silly rumors is as old as the hills, and for trolls every day is April 1st.
Then you have people with a vested interest in spreading rumors of one sort or another, often for political ends. Negative rumors about 'Obamacare' have been widespread in recent years for obvious reasons, likewise people on the left often expressed their animus towards the previous Republican administration by making up negative stories reflecting their view of how that administration would behave, or what would motivate them in the case of some otherwise random-seeming fact.
There are a great many people who are not especially concerned with truth, but with shaping people's behavior in order to bring about a certain result - whether that is getting people to buy a product or a book, or to change the price of a financial asset, or to create a more favorable political environment etc.
A lot of rumors are the result of poor understanding or misinterpretation. For example, there was a big rumor a year or two back that the US government was buying hundreds of millions of rounds of ammunition, sparking fears of everything from a conspiracy to drive up prices to an imminent imposition of martial law. The basis of the rumor was a government solicitation to bid on ammunition pricing, so that the government could lock in its ammunition purchases for the next few years at a fixed and predictable price, rather than being subject to spot price fluctuations which would make budgeting more difficult and possibly result in higher costs. However, to understand that that the government was looking for (essentially) a call option required a basic knowledge of finance and a fairly high level of reading ability to deal with the 'officialese'. It's not surprising that many people misinterpreted a request for a pricing guarantee as a solicitation for actual supply. There was also a misunderstanding of how much ammunition the government actually uses, with people who cheerfully fire off hundreds of rounds during their own practice sessions overlooking the fact that federal employees who carry firearms also have to take part in training and practice sessions where they expend large quantities of ammunition. More here: http://www.snopes.com/politics/guns/ssabullets.asp
Trolls shouldn't need much explanation; a tradition of spreading outlandish or silly rumors is as old as the hills, and for trolls every day is April 1st.
Then you have people with a vested interest in spreading rumors of one sort or another, often for political ends. Negative rumors about 'Obamacare' have been widespread in recent years for obvious reasons, likewise people on the left often expressed their animus towards the previous Republican administration by making up negative stories reflecting their view of how that administration would behave, or what would motivate them in the case of some otherwise random-seeming fact.
EDIT: here's an outstanding example right here on HN, today: https://news.ycombinator.com/item?id=7667068
There are a great many people who are not especially concerned with truth, but with shaping people's behavior in order to bring about a certain result - whether that is getting people to buy a product or a book, or to change the price of a financial asset, or to create a more favorable political environment etc.