The Thunderbird address book is where you'll keep all your online and offline contacts organized. If you're making the switch to Thunderbird from Outlook, Eudora or another email client you can easily import your contacts and even your mail and settings from said email client.
With "My Queue" you can quickly save videos to watch later.
To add an item to your queue just click the sign next to the video.
Once you've added a video visit "My Queue" to start watching!