Facebook Inc is getting less and less cool, at least among teens.

A report today by Frank N Magid Associates Inc found that the portion of 13- to-17-year-old social-media users in the US on Facebook slipped to 88 percent this year from 94 percent in 2013 and 95 percent in 2012. In the same period, Twitter Inc and messaging applications rose in popularity in that age group, the study showed.