When Comic Book Guy throws the sledgehammer into Steve Mobbs' image on the wall video screen (after Bart hacked into the newsfeed to play a joke on the Mapple Store shoppers), it is a reference to the "1984" Super Bowl commercial that introduced the Macintosh personal computer.
Bart tries to use a MyCube to help in his escape from the store, and all that happens is that the MyCube plays music. The song it plays is Lovin' You by Minnie Riperton.
Homer's dream references the 1992 Disney film Aladdin with its carpet ride, Robin Williams' Genie, and music in the style of A Whole New World.
As Homer dives into the river to save the Duff Beer, James Bond-like music is heard.
Mapple's undersea headquarters are accessed via a submersible that resembles a USB flash drive.
When Homer Run's into the old Springfield Mall if you look closely Hans Moleman can be seen to his left. But when the Duff truck crashes and Homer swims to save the beer, he's trapped in the truck.
When Krusty gives Lisa the MyPod, and when Lisa shows her music to Sherri and Terri, her MyPod is like the iPod Classic. But when the three of them watch the exclusive episode of Itchy & Scratchy, her Mypod is like the iPod Touch. The giveaway is that there are no buttons in the center, and the homescreen has apps.
Lisa owed Mapple $1200 for downloading her music, which cost $0.99 (or $1.00) for each song, but the bill would have said $1212 because she downloaded 1212 songs on her Mypod.
No, not an error. 1212 songs * 99 cents per song = $1,199.88.
When Homer is flying on the magic carpet, he's covered in his blanket, but when the camera zooms out, his blanket is gone.
When Bashir leaves the dining room if you look closely you can see that his eyebrows disappear.
Edit
Added by RobotShake
