. >> reporter: between homecoming and gymnastics classes, 17-year-old twins brooklyn and bailey mcknightent their every move and some on their youtube channel. brooklyn and bailey are now putting their own line of products branded with a double "b" in front of the 4 million subscribers. >> i would call it the every day line, t-shirts, wallets, pencils, notebooks. >> reporter: they recently just launched their own mascara, too. was merchandise something your followers were asking for? >> people were asking, what is that outfit? so we were seeing they were wanting the things we were wearing and decided to create something of their own to feel more connected to us. >> reporter: brooklyn and bailey didn't say how much they're pulling in other than the line is doing well. they're saving all that money they make for college tuition. >> on the weekdays we go to school, it is very normal. we have math homeroom, but we live a totally different life going to business meetings. >> reporter: another youtube star cooking up a success -- baker roseanna panzino. >> i just arrived on my first stop on th

. >> reporter: between homecoming and gymnastics classes, brooke and bailey mcknight document their every move and song on the youtube channel. they are putting their own line of products branded with a double b in front of their 4 million subscribers. >> i would call it like an everyday line, like we've got t-shirts, wallets, pencils, notebooks. >> reporter: they recently launched their own mascara, too. was merchandise something that your followers were asking for? >> we're seeing any time we post a t.d. the girls want the outfit we're hearing. >> outfit of the day. >> otd ss. we decided to create something of our own so they can feel more connected. >> brooke and bailey did not say how much they're pulling in other than the line is doing well. we're saving the money they make for college tuition. >> on a weekday we go to school, we have math homework, too, but at the same time we have this totally different life, going to business meetings. >> reporter: another youtube star cooking up a success story. >> it's ro, withal come to another nerdy nummies. >> reporter: rosanna has more than