Starting out three years ago with a Webcam in their bedroom in Kingsport, Tennessee, uploading quick beauty tips to YouTube, Elle Fowler, 23, and sister Blair, 18, have created a massive following, have big brand deals and have moved to LA where they are mobbed by teenage girls at malls.

Their YouTube channel has had 289 million views and has 1.6 million subscribers. Their vlogs have 43 million views and 800K subscribers. Together, they have 400K Twitter followers.

They have a big brand campaign going with Avon's Mark cosmetic line. This has been created by the Los Angeles-based Web studio EQAL.

We caught up with the sisters last week during Advertising Week where they were on a panel about web original content moderated by John McCarus of Digitas.

We asked them about how they built their authority as beauty experts; Elle says they are just "real girls" with simple advice. 

Of the brand associations, they say they only endorse what they would use and are transparent by identifying endorsements as sponsored posts. Got to keep it real.

Andy Plesser