The spotlight annotation acts similarly to the note annotation in that it allows you to link to various aspects of the YouTube network with or without text, but the only difference is it highlights a section of an existing video. Therefore, you can create aspects of your video that added with the spotlight annotation appear as custom links to your other YouTube assets. By placing the spotlight over a particular item within your video that section now acts a working link to other content.
This annotation acts simply as an added function for videos without a title built into the production of the video. Users can customize the color, font and size of the title box they wish to have for their entire video or if they wish to, they can cut their video in various sections with various subtitles. This annotation is more helpful for branding purposes because it helps clarify for the user what the video is and what company is being represented.
“A series playlist allows you to mark your playlist as an official set of videos that should be viewed together. Adding a video to a series playlists allows other videos in the playlist to be featured and recommended when someone is viewing a video in the series playlist. YouTube may use this information to modify how the videos are presented or discovered.”