Yahoo! is a global company and spends a lot of money serving up web content as fast as possible in London, San Francisco, or Tokyo. The central YUI files are on that same network, creating a shorter path from a user’s browser to required files needed to enhance a website. Pulling files from a separate domain also creates an opportunity for more parallel content downloads, circumventing the two requests per host limit in Firefox and Internet Explorer.
Yahoo! will be logging each request and its page origination, so if you are worried about privacy and providing pageview numbers to outside sources the hosted version of YUI may not be for you (grab a download, host your own).
A web widget feature
Version 2.2 of YUI, released on Tuesday, includes support for a new global variable named
YAHOO.env. Web widget developers can reference this variable to determine if YUI is already present on the page for additional functionality or before loading a conflicting library. It’s a useful feature for blog sidebars, letting your widget peacefully co-exist with a del.icio.us, Flickr, or MyBlogLog widgets/badges without unnecessarily weighing down the page.
I think the Yahoo! Interface Library will continue to gain traction thanks to its heavy development, extensions, and documentation. It’s already being used by large sites such as The Wall Street Journal and SmugMug and across the revamp of the Yahoo! network, which are some key votes of confidence important in new technology adoption.