What number is "1,234"? Ask an American and they'll say it's 1,234, but talk to a European and they'll say it's 1,234.
That's already bad enough, but it gets worse! Ask an American what number "one billion" refers to and they'll say one billion, but a European will think it means one billion!
Randomly having 3+ orders-of-magnitude miscommunications is a really dumb way to run a civilization. We gotta pick one guys.
Market resolves based on whether one set of unambiguous methods of talking about numbers reaches at least 95% adoption among the relevant group of people. (That being everyone who uses Arabic numerals for the first issue, and all English speakers for the second issue.)
This market is about numbers only, not dates, systems of measurement, or other places where humanity has not yet gotten its act together. (It does however refer to any other serious numerical ambiguities that I didn't mention above.)
