After initial contact last year that did not lead to an offer, I was again contacted by Google.

I went to the New York office for the full-day, six-part interview. I will not disclose the specific questions asked, as I agreed and signed to do so. However, these should not be a mystery or secret for anyone; they are about algorithms, mathematics, sorting, hashes, system design, and multi-processor, multi-site problems, etc. If you rehash your university material, read all the recommended basic algorithms and practice material, none of these questions should come as a surprise.

One thing I will say, though, is that not all interviewers are equally enthusiastic. I do not know if this is by design or not, but out of the six interviews I had, one guy seemed outright disinterested, while another guy was courteous enough to give proper questions but didn't seem to have his heart into it. I do understand to some extent, as the interview process is grueling and you will be worn down at the end of the day. I assume it is equally an effort for the interviewers, especially if they have to do multiple interviews (and reject the majority). Make sure you are rested the day before.

Anyway, do realize that you cannot afford any clear negative reviews. The hiring committee will allow one negative if you have great reviews from the other interviewers, but two negatives will kill any hopes, regardless of how smart or good you are. Make sure not to antagonize any deadbeat interviewer you might run into. And do practice whiteboard design and coding. It is that important.

That said, I had a lot of fun with most of the interviewers. The most important aspect is that they want to see if you are what I understand to be 'googly'—smart, inquisitive, investigative, curious, a problem-solver, etc. You will get challenged. How you approach a problem or question, or how you proceed with each monkey wrench they throw at you, is more important than getting the 'perfect answer.' There were no questions about how many elves you can fit in a Coke can, etc. I had very interesting and fun interactions with the interviewers, talking about the topics they asked me about and also wandering off-topic to other computer and non-computer interests.

One surprising thing is that I found out Google actually contacted most of the professional references I provided. I didn't mind this, as I have very good backgrounds and well-respected references who would vouch for me any day. Please make sure to put in your best references – those people who have had good experiences with you and can vouch for your work and qualities.