According to Comic Book Movie on Sunday, director James Gunn gave his explanation of the Infinity Gems in "Guardians of the Galaxy" which is key to tying it all together when it comes to the Marvel Cinematic Universe. Also, Gunn explains the ensemble of a Marvel Easter egg laden museum as owned by The Collector, played by Benecio del Toro, who resides in Knowhere.
Director Gunn did talk about how he was elated to build upon the Marvel Cinematic Universe an awareness of the motive behind Thanos' desire for the Infinity Gems as he acknowledged that Joss Whedon's Avengers characters pretty much have little awareness behind the cosmic forces that Tony Stark, Black Widow, and Hawkeye could not even fathom encountering nor were ever trained for. Even Stark developed a form of anxiety related attacks after the Battle of New York.
Gunn expressed his desire to bring Thanos and the Infinity Gems into the film as he is a lover of the Mad Titan and also highly desires those audience participants who have seen Whedon's "The Avengers" to also see his film.
"We talked early on about having Thanos in the movie, which, believe me I was excited to have Thanos in the movie because a) I love Thanos and b) I want people who have seen The Avengers to go see this because we're connected to it."
As far as what Infinity Gem does what as already portrayed in the comic book story line, Gunn clarified that the particular gem that is contained within the orb is actually the Power Stone. It's been established that the stone from "Thor: The Dark World" that is contained with the Aether is the Reality Stone and the one from within the Tesseract is the Space Gem. This leaves only three of the six left to go, which means the Mind, Soul, and Time Gems.
Thanos, played by Josh Brolin, eagerly awaits the collection of all six stones as only a certain breed of person is able to handle and control such power. As one may have already noticed, the slave girl to The Collector had already been destroyed by the gem as she grabbed it bare handed, but Star-Lord, with the help of his co-horts and his genetic lineage that could lead back to his father as portrayed by J'Son of Spartax in the comic book.
Though he isn't mentioned by name in the film, he is mentioned by Yondu Udonta at the end of the film only as his father. It seems Yondu was suppose to acquire Star-Lord and bring him back to J'Son.
Gunn also explained the different Easter eggs such as chambers containing a Dark Elf from "Thor: The Dark World" and a Chitauri being from "The Avengers". Also Cosmo the Russian telepathic dog makes his great escape. Gunn even mentioned a rather unnoticeable Easter egg from his film "Slither" was also present.
"There’s a lot of stuff in the Collector’s Museum. And for me, it was mostly just really fun. As a Marvel fan, giving the actual fans something that they can freeze frame on their Blu-Ray at home and just kind of pick out everything that’s in there. So there are, I mean, seriously all those boxes have something interesting in them, so it’s pretty fun."