Developers who have occasion to interact with YouTube videos should prepare for a slight (but important) change concerning video page URLs. They’ll be altered just enough to screw a few things up.
The change is as follows: a question mark in the URL will be replaced over time by an exclamation mark. And a post on the YouTube API Blog promised, “The old-format URLs will continue working indefinitely when used for browser navigation, so if your web site has existing links to YouTube video pages, you don’t need to worry about them breaking.”
But the post then continued, “What we’re concerned about is developers who have written code that takes a user-supplied YouTube video page URL as input and attempts to parse out the video id using a method that assumes there will be a ? character in the URL. If you have such code, you will need to make it flexible enough to support both styles of URLs.”
Get ready accordingly (YouTube would like you to use its oEmbed service) if this move has the potential to upset anything you’ve developed.