When using the Sharing option on the Player, there is an ability to post a link to the player via Social Channels such as Twitter.
The default message that will send is 'Check out this awesome video', but it is possible to change that.
There are two places for adjusting this message.
To adjust it for an individual player, use the Player > Settings > Social tab.
To have the default for all future players adjusted, use the Content > Defaults > Social tab.