Editor's note: updated at 5:00 p.m. 2/14/13 with comments from Aleksandra Milicevic While couples celebrate Valentine’s Day, singles looking for a casual date may be surprised to find that their smartphone...

On the first day of class when professors hand out the syllabus, one particular regulation that can be found in most courses is the over-emphasized rule: “No cell phones.” But with the vast increase...