First up –YouTube added a killer feature on Wednesday called YouTube Annotations. You can add text bubbles and links inside of your video, allowing you to cross reference other videos and create added bits to extend your video with notes, descriptions and commentary. These can be turned on or off by users that find them annoying. To get an idea on how cool this is, check out the examples YouTube has online—including an impressive interactive magic trick.

One of the best things about YouTube is that you can easily embed your video into any website. But some websites with interactive content aren’t quite as easy to use, and it can be a painful experience trying to embed and share their applications. Enter OEmbed, a new proposed standard designed by Pownce developers Leah Culver and Mike Malone. The purpose of OEmbed is to simplify the process of embedding any content in a webpage. You put in an OEmbed tag and it gets all the required information from the host. So far, not all websites support OEmbed technology. But since Flickr and Viddler are supporting it, you can expect to see other big names following closely behind.

Of course, embedding content is just a small portion of what web 2.0 is all about. The newest thing is taking web applications out of the browser and onto the desktop. The latest to take advantage of this new technology is Pandora, the online music engine that streams a radio station of free music according to what you like. Now that Pandora has been emancipated, you can listen to music all day long without worrying about accidentally closing your web browser.

iTunes doesn’t have this problem, since it works outside of your browser anyway. And if you use iTunes a lot, you’ll find iConcertCal to be a great plugin. This searches through your and generates a calendar, showing you when your favorite bands are coming to your city. It runs on both Mac and Windows, and has world wide searching capabilities. The mac version can even sync with iCal.

On the other hand, if you’ve got a band you’re trying to promote, then you should check out ArtistData. It’s a website that takes in whatever news, data or concert info you’ve got and it pushes it out to multiple websites all out once, promoting it on YouTube, Last.FM, MySpace and a whole lot of others. It can import and export information like tour dates, status updates and videos.