This is something I never really knew much about, just that a lot of my friends, when I mentioned being a Mobb Deep fan, said they were more 2Pac fans, that 2Pac had tore them a new one on his reprisal to "Drop A Gem on Em" but I'd never understood why you could be a fan of one or the other but not both.
So I read this Wikipedia article. Yeah, Wiki can be edited by anyone and its not the most plausible source all the time but the author really seemed to have a grip on the topic and explained it in a pretty well removed and unbiased way - so I'd take this as a pretty reliable account.
http://en.wikipedia.org/wiki/East_coast_west_coast
So, being a Mobb Deep fan I wanted to see just what was going on and whether they'd really instigated anything between themselves and 2Pac. Per this article at least I found a lot of things out that I didn't know and I doubt my friends know either. To me it sounds like the guy went crazy and just started talking smack about everyone and anyone, just to do so. I can understand being raw about getting shot 5 times in a rival city but it seems like he dragged all kinds of people in who fundamentally had no beef with him and in the end its like he lost all sense of discretion. The story with the Mobb was that Outlaws showed up to one of their shows and got snubbed. After all that 2Pac had said and done already, it doesn't surprise me in the least and if I were them I think I would have too. I hate to talk that way about the deceased, 2Pac had his talent and was a good rapper, but I can't take his side on this one.
Anyway, these are the two songs in question between the Mobb and then 2Pac. My friends look at 'Hit Em Up' as a reprisal against them, in part it was but not only was he dissing everyone (the people he had beef with Biggy and Sean 'Puffy' Combs) and Mobb Deep but this article talks about the fact that with 2Pac, everything he starts saying about Prodigy's sickle-cell and seizure on stage, that's the same thing he was saying, after Outlaws got snubbed at their show, that actually got the song 'Drop a Gem On Em' written - ie. it was really their reprisal. They talked about shooting him through the mouth if he ever came through based on what he'd said.
Anyway, here are the two tracks in question off of Youtube, make your own call (and yeah, there's explicit lyrics here - if your not a fan of that I wouldn't recommend clicking these links).
[youtube]http://www.youtube.com/watch?v=N4HjsZqOaQ0[/youtube]
[youtube]http://www.youtube.com/watch?v=5ACMDW42eOI[/youtube]
Anyway, its one of those semi-obscure bits of recent history that people talk about, make abstract references to, but people really don't know much about it. I at least like to stay on top of this stuff just because I like having an educated opinion on it.