You are successful, knowledgeable, well-educated and enthusiastic. You want a job in a high profile, successful company, like Yahoo!, and Yahoo! is hiring. The interests of the parties involved coincide, you just have to show all of the qualities above in the interview. We know you are likely to be nervous as you really want the job and here is some tips to help you deal with it, based on my experience interviewing people.
We are looking for enthusiastic, energetic people. Don't appear dull or distracted, "jump" on us so we will see that you are interested. Do ask questions, as what you ask also tells us what you think, your level of engagement and interest.
Be ready to talk about the items on your resume. If you did a project 5 years ago and you cared to put it in your resume, be able to succinctly describe what you did and why and what the results were. And I literally mean, be prepared, cause if you start saying "hmmm let me see", this looks a little odd.
We will ask you to solve a problem or two (see below for a couple of examples), some problems maybe technical, some maybe more philosophical, the point always is that even you may not know the answer right away, we need to see the thinking process, the solution, your ability to connect things in a logical pipeline. So do show us the solution as you arriving to it.
All PhD level people coming to the interview are expected to present a talk on their previous work (e.g. the dissertation topic). View it as a serving in tennis, you have the edge to talk about things you want, use this opportunity wisely, be well prepared and do your best to deliver. Anticipate the questions and prepare the answers. It often makes sense to skip the details in the presentation, move the slides with the details to the back so you could show them if the question arises. Also, consider the group interviewing you and show the connection between your past work and experiences and group's projects.
