I've only been reading the X-books since 2000 (Yeah, I'll admit it... I got into X-Men regularly after the first movie. Prior to that, I only watched the cartoon). In those six years, I've been able to learn pretty much everything that happened in X-Men since 1963 and been able to followed every single bit. It's honestly not that hard. Even the casual fans I know are able to follow it. I mean, yeah... My brothers don't know what a Fastball Special is... But they sure as hell can tell the difference between Henry McCoy and Kurt Wagner.