That means investors effectively would be receiving a negative yield on the note.

WSJ: U.S. Stocks Tumble, Treasury Yields Sink to Record Lows

In that event, retailers risk receiving their most extreme negative reviews or the user deleting their app altogether.

FORBES: When Mobile Shoppers Get Mad, Don't Just Leave Them Your Number

According to the NIAAA, about 25 percent of college students report negative academic consequences of their drinking, including missing class, falling behind, doing poorly on exams or papers and receiving lower grades overall.

FORBES: A Sober Assessment of High-Risk Drinking on College Campuses

And while that may sound good for bargain hunters, and perhaps even more importantly for Japan's ageing households receiving fixed pension incomes, if prices continue to fall for a prolonged period, it actually has a negative psychological and business effect, some economists argue.

BBC: Q&A: Bank of Japan's inflation target