I had a first 30 mins phone interview, 4 interviews in their office in London and 3 Skype interviews afterwards. It was a waste of time. I spent 8 hours in interviews/emails to receive a final feedback that I was not in their 'culture fit'. They were not at all organised and I think the job was significantly less technical than I thought, as there were no difficult/technical questions. I am not sure what they are looking for, but they did not seem to be realistic about their expectations at all. Plus I did not find any of the interviewers extremely special or highly intelligent people, as they kept telling me that the AppNexus employees should be. They did not even know with whom I had the previous questions, so they asked me the same questions over and over (at least 5 times), they were making huge mistakes about information on my CV (one mistook my current employer with a competitor) and I found it very, very worrying that a VP of a tech company does not know how to use Skype properly.