Q. Who uses SWFObject/FlashObject?

A. Websites like The Library of Congress, Adobe.com (A slightly customized version), Windows.com, YouTube.com, skype.com, Snapple.com, it is included with Adobe Photoshop (in the Flash web photo galleries) and thousands of others. Colin Moock also suggests it as an alternative to the Macromedia Detection kit.
SWFObject:FAQ

大手が使ってるようなので利用することに。Youtubeが使ってるのに驚き。Adobeのスクリプトより使いやすいのと、（使わないけど）Express Installにも対応してたりして便利そうだったので。