Friend suggestions: As mentioned in a previous post, we've started the first phase of the "find your friends" project with a module on the homepage that makes friend suggestions based on the email addresses of people with whom you've shared videos on YouTube in the past. (Suggestions based on your Gmail address book will come soon.) Recommendations will be limited to people who have the "let someone find my channel if they have my email address" flag set.
Activity subscriptions: To this point, subscribing to someone meant never missing any of their uploads. But now, any new subscription you make will notify you of all public actions that user performs (uploads, favorites, ratings, comments, etc) in your Recent Activity module on the homepage. This should make it a lot easier to find cool videos: just see which videos your friends and other curators choose to interact with. (We've been calling this project "subtivity" internally.)
Trending Topics: When there is a spike in searches on a given topic, we are beginning to tease that out on our browse pages to help you see what the world is watching on any given day. You might see the queries appear in a "Trending Topic" spotlight on that category's browse page or at the bottom of the page. We're testing how this performs and if it does well, we'll find a permanent home for it on the browse page and potentially more broadly on YouTube.
Sticky HQ: When you switch to view a video in high quality and lean back to enjoy the wide player experience, having to lean forward again to switch the experience back on, video after video, can be a real chore. Moving forward, your choice is "sticky," meaning that when you "go wide" it will persist across your session. We're looking to make more of your video quality choices simpler and persistent so we'll be watching this one closely.
Effortless "More Comments": Replacing the page-based system, we will now have a "Show More Comments" link at the bottom of comments that, when clicked, quickly appends 10 more comments to the end of the list.
New Discovery Features in Insight: We've released three new features in our analytics tool that should give you more sophisticated ways of using Insight so you can better serve and understand your audience. Now you can access a "discovery over time" graph that combines data about your views with where those views came from; a "views from mobile" section where you can see which of your video's views came from mobile phones or platforms that use our APIs; and "views from subscribers" where you can more deeply understand how the homepage subscriptions module, the subscriptions page, and subscription email drive views of your videos. Full post in the Biz Blog.
Resume where you left off: Let's say you're watching an epic (read: longer than 20 minutes) video, and you get distracted and click away. The next time you return to the video, it will resume where you left off watching, assuming you've watched more than one minute of the video and there are more than three minutes left.
Subscriptions comes to Shows, Movie Trailers: Subscribe to your favorite shows on YouTube to never miss a new episode. Find the show you want to watch, go to its About page, click Subscribe, and episodes that hit your inbox will indicate the name of the show (as opposed to the name of the channel or provider). In addition, you can also subscribe to our movie trailers page to never miss any of these film promos.
Poster art in Movies: Move over, thumbnails! Films in our movies section can now display vertical poster art if the partner provides it.
Best, The YouTube Team