[quote name='vonoliveramora']hey guys whats this cerberus network? is digital copy more worth it than physical copy? i am opting to get physical..?! coz DL size is so big! and if i delete it for some space, i have to DL it all over again! right?[/QUOTE]
A clever, yet morally questionable method on EA's side, which pretty much guarantees that they'll get at least "a portion of their money back" when you buy an used game from a friend or a local retailer.
Some content on the Mass Effect 2 game disc is available right from the start, but some has to be unlocked by entering a unique (one-time use only, provided on a paper code-sheet added to the game box) "Cerberus Network" code online. Which, as you may have guessed already, stays signed to a given user.
In Mass Effect 2 the locked content is an additional NPC (along with his storyline, missions etc.) - Zaeed, one side mission (a piece of back story, especially enjoyable if you have played the first game), a quest which involves you piloting a hovering vehicle, some equipment (shotgun, heavy weapons, unique armor) and the interactive comic.
Without the interactive comic you're pretty much unable to understand the story of the first Mass Effect (if you haven't played it already that is) and, what's even worse, you can't make any choices in order to make your Shepard unique.
The default choices, which the game forces on you if you haven't played the interactive comic, pretty much make you the most evil son of a *khem* that the galaxy has ever seen.
Long story short: if you buy an used Mass Effect 2 disc, you have to shell out additional money for some pretty damn important content. If you are unable to connect your PS3 to the Internet... Tough luck.
I have no idea how it works with the digital version of ME2 unfortunately, sorry. That's what I'd like to know as well.