Over 2,000 VidCon attendees participated in a "cellphone wave" last Saturday, at the convention's Prom Night.VidCon is an annual convention for YouTubers and other internet personalities, and has been held annually since 2010 in California. This year, participants ended the conference by joining in a cellphone wave, where you use your smartphone's flashlight feature to participate in a rolling wave of lights.VidCon's attendance has nearly tripled since 2012, with an estimated 19,500 attendees this year. As platforms like YouTube and Vine become increasingly efficient starmakers, more fans flock to VidCon in the hopes of meeting their favorite content creators.