14 DAY TRIAL // YouTube is rolling out an updated version of the site, which should be a lot snappier than the current one. The trick is that the new YouTube doesn't completely load new pages as you move around the site, but rather just the content that needs updated.
This new AJAX interface has been in testing for a few months and YouTube has said that it's one of the several big steps it's taking to speed up the site.
With the new UI, switching from one video to another doesn't need a full page reload, instead, just the actual video and its metadata, i.e. title, description, likes and comments, along with the related and suggested videos are pulled from the Google servers.
That's still plenty of data, but by not requiring a page reload, YouTube gets rid of a lot of HTTP overhead as well as the need to download the HTML and JavaScript code as well as all the other resources that are static between page changes.
This new version of the site now seems to be enabled by default for all Chrome users, though you won't see it everywhere. Instead, it triggers when you use playlists or switch to a new video from the related list.
Still, it does look like YouTube is getting closer to making the new site the default for everyone, though a full rollout is sure to take a few months.
If you're not sure if this new YouTube is enabled for you, keep an eye out for a red loading bar at the top of the page when switching between videos.
Speed, for Google, is very important and for good reasons. Its studies have shown that users have very little patience and the difference between a page that loads in one second and one that loads in two seconds is quite significant.
For example, Google is now recommending that mobile website developers build their sites to load content above the fold in one second or less, i.e. to give visitors something to see or do within one second and load the rest of the site in the background.