You can add a timestamp to any YouTube video in just a few clicks from the desktop website on your computer but not from YouTube's iOS or Android app. Until YouTube adds a "start time" when sharing videos from the mobile app, you'll have to use one of these workarounds on your phone or tablet. Why would you even want to use shareable YouTube links with start times? Tacking a start time to a YouTube video is an easy way to bookmark a specific part of the video to come back to and reference lat...