Posting videos in apps and Web services has become a mainstream online activity, and not just for our kids. More than three-quarters (78%) of US adults watch online videos and the percentage of them who post them has more than doubled since 2009, from 14% to 31%, according to the Pew Internet Project. “That includes 18% of adult internet users who post videos they have created or recorded themselves,” Pew says. The fact that big social media companies now offer video-sharing has certainly fueled momentum this year (Twitter introduced its Vine app last January and Facebook’s Instagram added video six months later). So has sheer convenience. The vast majority of US adults (91%) own cellphones, which means that most have the ability to shoot and post videos just about anywhere any time. Pew says 41% of cellphone users actually do shoot videos, 40% watch them on their phones and 20% use their phones to post them online. [Then of course Webcams on computers have joined video on tablets and phones in making video (via Skype, Google hangouts and Facetime) a basic communications tool.] As for topics, “comedy, educational and how-to videos top the list” of preferred subjects for online video-viewing, Pew says, and everyday, spontaneous moments involving family and friends is the favorite thing to share.