"This could mean working on particular projects within the organization which like external visibility (e.g. Android) rather than projects which don't (e.g. AdWords plumbing -- presumably Google will pay you a lot of money to do that, but consider it compensation for not being able to talk about it)"
Perhaps counterintuitively, as far as I know, people who work on Ads internals aren't paid any more than people who work in more visible/desirable parts of the business.
This maybe just an observation that life isn't fair. Some jobs both pay more, are more enjoyable, and look better on your resume. Some people are attractive and successful. It is definitely worth keeping this in mind when considering your career, a difficult job doesn't automatically accrue karma faster than an easy job.
Perhaps counterintuitively, as far as I know, people who work on Ads internals aren't paid any more than people who work in more visible/desirable parts of the business.