"The urban legend (that Facebook is losing younger users) flows more often than not from surveys people have done of younger users that indicate that they're using other social services ... much of the concern stems from the assumption that this is a zero-sum game, and that's not how we see it, " Ebersman said.

CNN: Survey: Teens' enthusiasm for Facebook is waning

And this beneficial outcome follows, remember, on the extreme assumption that voters act not out of concern for the greater good, but out of pure self-interest.

ECONOMIST: Out of anarchy

For investors, there can be concern that an investment manager is making overly optimistic assumption about illiquid assets in order to boost management fees that are calculated as a percentage of assets under management.

FORBES: Will SEC's Settlement In Valuation Case Be Part Of A Trend?

At the time of nationalisation the government said that any subsequent valuation for compensation purposes should be based on the assumption that Northern Rock had not been a going concern.

BBC: Appeal defeat for Rock investors

UNESCO's concern about women's marginalisation from ICT is based on the assumption that women will benefit less from new educational and employment opportunities.

UNESCO: Communication and Information