Your Google PageRank went down immediately after some of your linking websites lost their PageRank or cut their links to you. Toolbar PageRank updates rarely so you couldn't see it until now. Timing with Panda is accidental and not related to your PageRank change. Nothing to worry about and keep up with great content and good design. New thing to keep an eye on is user experience, however links are still very strong as a factor so you should try to earn great links as well.

We have implemented something similar in the past with no negative effects. Same deal with tabbed content. If this type of display is convenient for the user and not only served to search engines then you're within the search engine guidelines. Even if you do get in trouble (very unlikely) there is always a re-inclusion request in which you can explain things to Google.

One thing to keep in mind is Google's cloaking filter they've been writing about this recently as they start to compare what is displayed to them to what user would see. I cannot know exactly to what extent the site may vary in appearance with your overlay feature.

Visit: Google Webmaster Tools > Labs > Instant Previews

See the last paragraph in the attached image.

dejan-seo-preview.PNG

Are we able to see this IP / domain?

Thanks for your valuable input.

If you are to sort the factors - I guess titles would be at the top of your list, what would follow?

Hey guys, what are in your opinion top ranking factors for YouTube optimisation?