Good question, I often read the Matt Cuts blog to keep up to date with all this stuff. I leave the link to his blog, with some good info: http://www.mattcutts.com/blog/caffeine-update/
Use that scroll wheel on your mouse and find all about caffeine in this thread In one of those posts ull find a link to all there is about caffeine update..
Caffeine is/was just an operating system backend update to make things faster and more expandable, bit like going from Win98 to WinXP. It's not the Caffeine update you have to worry about, it's the extra things the speed increase will allow them to do that may become the problem. The Food and Drug Administration also state that too much Caffeine can be bad for your health