Wall Street analyst Ken Sena has revived the rumours that Facebook is losing its lustre for younger users. “Accelerating U.S. traffic declines and younger demo exodus create fundamental concerns,” the Evercore analyst wrote in a note for investors. “U.S. comScore data show Aug time spent down 12% pro forma (down 14% reported) y/y. The declines are primarily attributed to age groups 12-17 and 18-24, which declined 42% and 25%, respectively.” As we’ve previously reported when covering comScore’s Vevo numbers, the company’s stats cover websites on desktop computers, rather than mobile – and mobile is where Facebook is experiencing its sharpest growth at the moment. Even so, this won’t be the last suggestion that – with parents and grandparents happily sharing and over-sharing on Facebook – the youngest generation may turn away from the social network.