Pure speculation.  1) Internet, followed by 2) Ubiquitous smart phones making it to teenagers -- and&#x2F;or the laptops that also seem to be ubiquitous in education, these days.<p>A personal place to look things up, less monitored than the family or library computer.<p>(So, the other side of the &quot;porn epidemic&quot;?  To be clear, not attributing porn per se, but rather range of information available to those who seek it out.)