How do the Xbox 360 addon discs work? (Borderlands, Dragon Age, etc.)?

These are what i'm referring to,



http://www.bestbuy.com/site/Borderlands+鈥?/a>



http://www.bestbuy.com/site/Dragon+Age%3鈥?/a>



Could me and a friend both receive the expansion from a single disc and play together, or would we both have to buy our own copy? Also, do you put in the expansion disc and run off that one just as if the game has multiple discs, or do you just put it in your console, check it off, and you put your original disc back in?



Lastly, are these a good deal, or would I just be better off using Microsoft points?



Thanks!How do the Xbox 360 addon discs work? (Borderlands, Dragon Age, etc.)?
You put them in, let them install into your hard drive and then you put the original game disc back in to play it. Yes you can give it to your friends so that they can have it too...and the disc for borderlands is a good deal, but the dragon age one im not sure, if you want to share it with your friends then go for the disc but i think microsoft points would be better for buying the dragon age expansion.