NextRoll Software Engineer - New Grad interview questions

I was looking for companies to apply to and I found AdRoll on a couple "promising companies" lists. Ad-tech companies tend to work on problems that match my interests (AI, Big Data, back-end systems) so I applied. A recruiter contacted me almost immediately and we set up a quick phone screen where we talked about my interests and the company. Following that were two technical phone screens with engineers. My first phone screen was given by a software engineer and involved coding on a collaborative editor (stypi/collabedit). My second phone screen was given by a data scientist and covered streaming algorithms for sampling and analysis (no real coding, we just talked). After the Technical screens I got a call from the CEO and we had a brief chat about the company (including a short technical question) and then they flew me out to SF. I had 4 onsite technical interviews where I was asked about algorithms and system design. All the interviewers were really laid back and refreshingly candid when I asked questions about the company. At the end of the day the CEO took me out for lunch and let me ask him questions about the company. I didn't know much about start-ups so I asked about equity and valuations and AdRoll’s strategy/competitors and such. It was really cool to hear the CEO’s perspective on things. That same night I got a call from my recruiter saying they’d like to give me an offer. I was very impressed with the company and the people I talked to and the offer was competitive so I decided to accept.