If you're sending links to #youtube, the share button will send the text, but if you copy and share the actual Web address it will also show what the video is and a thumbnail! However if you do this from your mobile phone device, it will autoconvert it to an 'm' address instead of 'www'. If you therefore change 'm' to 'www', it will also show what the video is and a thumbnail!

Otherwise it's just links that noone can see and are less likely to open. 😊