The blog entry notes that .flv files can be played as well as saved to m4v. This means that the video format more widely utilized in the video sites such as youtube etc will be natively supported by QuickTime Player. But there is more: when this version of QuickTime is included in the version of OS X included in iPhone/iPod Touch, it will allow you to watch those videos, without prior conversion, on your iPhone or iPod Touch. I think this fact deserves being noticed, as it will save quite some time to many people interested in .flv videos.
In the past QuickTime users have installed third party components such as Perian to support the FLV format.
Read More [via 9to5Mac]