[myelin]

Another Googler here, speaking directly to the "working on ads" point: Ads is huge, but it's not hard to stay away from it if you're not interested. I worked in Cloud (App Engine) for four years and am now working on Chrome OS, and out of all the people I've worked with who transferred to other teams, I've only heard of 2-3 who moved to Ads.

Internal transfers are pretty easy too; it's not unheard of to switch teams every 18 months or so, so when you get sick of working on whichever huge distributed system you start with, you can go work on consumer hardware, one of the various operating systems, Google Maps, the Chrome browser, a site like Google Docs, one of the many iOS apps, one of the Cloud products, etc etc.

Working at Google isn't the wonderland some articles paint it to be, but it's definitely not boring, and there are lots of interesting people and projects around. You might not find your job itself to be super meaningful, but being surrounded by thousands of other engineers who all would like some meaning in their lives makes for an interesting community, and tons of fun little at-work side projects.