advertising on social networking sites? >> listen, social media is transformative. over half of america looks at their facebook account every day. they use it on a regular basis. i would like to start with a light touch. i'd like to start and make again this iterative. we probably won't get it 100% right at first. >> so warner wants co-sponsors for this legislation. that's what he's seeking. what about the bigger issue? the ongoing investigation into the connection between russia and the trump campaign? i asked warner if he has any evidence of coordination. >> listen, i'm not going to draw any final conclusions until we hear from all the witnesses, until we hear all the stories. it is a problem though, brian, and i share, i know, your and some of the viewers' frustration. every week there is a new thread to follow or new revelation