YouTube recently has added a orkut sharing button to the list of sharing thumbnails. Previously, you had to copy & paste the video URL to post the clips to your orkut favorite videos. Now you can simply share your favorite videos using orkut sharing button directly from YouTube.
Previously, YouTube promoted only 2 social networks - Myspace and Facebook - so now with adding the orkut thumbnail.
YouTube now promotes orkut as well as the other ones, even though Google owns orkut.
Orkut officially launched orkut themes which are still not live for all users, but you can choose from different themes depending on your choice even if your profile has not been provided by this feature yet.
Orkut themes seem to be similar to iGoogle themes, so the most of them were created for iGoogle. 
If the new feature isn't available for your profile yet and you want to see the new themes, you can install Greasemonkey userscripts from Orkut Plus blog to have a feel of orkut themes.
