First employees have to deal with a lot of gruntwork. Possibly more than the founders, because they're often the ones stuck setting up the production servers, dealing with customer complaints, hacking through that sticky bug, firefighting, training/interviewing new employees, and generally doing all the boring stuff while the founders are out sealing business deals.
As for Google - it's what you make of it. I know some people who've gotten stuck in a narrow corner of the company, but I've personally been exposed to a pretty deep cross-section of the search stack, and worked on some fairly exciting projects. Working for a big company doesn't excuse you from actively managing your career - if something exciting is coming up, volunteer for it! And nobody can stop you from working on other stuff - if there's something interesting, just go hack it up and ask for forgiveness later.
As for Google - it's what you make of it. I know some people who've gotten stuck in a narrow corner of the company, but I've personally been exposed to a pretty deep cross-section of the search stack, and worked on some fairly exciting projects. Working for a big company doesn't excuse you from actively managing your career - if something exciting is coming up, volunteer for it! And nobody can stop you from working on other stuff - if there's something interesting, just go hack it up and ask for forgiveness later.