I applied online. The process took 3 weeks. I interviewed at MediaMath (New York, NY) in Sept 2017
Interview
Phone screen with recruiter > take-home assessment > in-person 'meet & greet' with hiring manager > in-person meeting with rest of team and final presentation.
I found the process to be in-depth and rigorous (in a good way), without being overly formal or one-sided in favor of the employer. The talent team did an excellent job of facilitating the dialogue and maintaining forward momentum, and the PSO team was transparent, honest, and intellectually engaged.
Interview questions [1]
Question 1
Tell me about a situation in which you had to deal with an employee's performance and how you handled it.
I applied through a recruiter. The process took 2 weeks. I interviewed at MediaMath (New York, NY) in Oct 2017
Interview
(preface: didn't receive offer due to lack of management experience, which I'll concede as someone with < 3 years of full time work experience)
Pretty straightforward interview process. Fielded InMail from recruiter, had an initial vetting call for 30-45 minutes. As a follow up, the recruiter e-mailed me a case study brief and accompanying data set in the form of a spreadsheet. The ask entailed running a few different attribution models and putting together a presentation with derived insights and recommendations on incorporating those learnings into the marketer's next program. I submitted this back to the recruiter, and after it was reviewed, they wanted me to speak with the hiring manager over the phone. Conversation went fine, no crazy questions or anything unexpected.
Overall the process was pretty smooth, the recruiters were responsive and helpful in understanding the process.
The one piece of negative feedback I have was that the hiring manager didn't review the case study or deck I spent 2-3 hours preparing at his request, so if you're asked to do something similar, I'd view it more as an administrative hurdle that you need to simply "pass" and wouldn't put too much time into it.