We're still a little perplexed about this, but The HD Room has it on authority that the Blu-ray rendition of Mamma Mia! will boast a Blu-ray first: shareable video commentary. Trust us, we had the same reaction that you just did. According to the specs, the "My Mamma Mia! Commentary" will allow users to "record their own video commentary while watching the movie and share it with friends," though we suspect you'll have to own a BD-Live-enabled player in order to do so. Additionally, the film will be presented in 1080p widescreen with a 5.1 DTS-HD Master Audio track, and it'll offer up on-screen lyrics for 22 songs, the Gimme! Gimme! Gimme! music video and a number of less enthralling extras. Expect the BD to ship day-and-date with the DVD on December 16th for $39.98 (MSRP).