Advertising revenue will be key in Reddit's (RDDT) earnings, says LikeFolio's Megan Brantley. She says Reddit web visits have grown 80% year-over-year while Snapchat slipped 30% over the same period. Megan believes this "captive audience" gives advertisers, and Reddit, a chance to capitalize on consumers. However, the rate of growth will prove key in its after hour report.