I first met Brian O’Kelley in the summer of 2008, when he was looking to raise his first institutional round of funding for AppNexus. Brian had a vision for how the online advertising market was going to evolve and believed that building highly scaled services for both sides of the industry – publishers that want to sell ads and marketers who want to buy them – would enable a more efficient and cost-effective marketplace. Software, data, and machine learning ultimately enabled ad transactions to occur programmatically and in real time on the AppNexus platform.

We at Venrock believed in Brian’s vision, but that was not the main reason we invested. We look first and foremost for special entrepreneurs, like former Venrock entrepreneurs Gordon Moore at Intel, Steve Jobs at Apple, Gil Shwed at Check Point, Steve Papa at Endeca, and more recently Michael Dubin at Dollar Shave Club. We call these folks “Forces of Nature”.

While Venrock does not have a formal or complete definition of “Force of Nature”, they do all share the following characteristics: they are scary intelligent, have far reaching vision for a market, think very big, and are EXTREMELY competitive.

Brian had all of these characteristics in spades!

I prepared an early investment description for my partners at Venrock called an NDFM (New Deal First Mention). This memo is designed to briefly describe the business for the broader partnership team to contemplate while an investing partner begins the diligence process.

Click here to read our original investment memo!

I was very interested in the business opportunity, as Venrock had invested in plenty of adtech businesses including DoubleClick many years before, but I was mostly excited about working with Brian. I really believed he was a “Force of Nature”.

One thing about “Forces of Nature” is that they stand out and pretty much everyone who knows them has an opinion on them. The opinions on Brian were consistent that he is a visionary and very smart, but were all over the map in terms of his ability to build and lead a company. The more time I spent with him, the more he grew on me, and I believed he had what it takes.

We then led the first institutional round at AppNexus investing $5.7MM for more than 20% ownership. When our investment was announced, I had two other VCs from other firms reach out to me and say I made a mistake backing Brian. This had never happened to me before, but in some ways I liked hearing it because non-consensus deals tend to have more upside (and downside) than straight down the middle deals. When I shared this feedback (but not the names) with Brian, his reaction was predictable for a “Force of Nature” … he laughed, said they are idiots and we are going to build a killer company to prove it.

While sitting on the AppNexus board, I challenged Brian that I would ultimately measure his performance not on the outcome of the company, but on the quality of the team he recruits, develops, and leads.

Well, Brian has clearly graded out as an A+ CEO as he has built an absolutely, positively world-class management team in NYC. They helped AppNexus fulfill Brian’s original vision by enabling hundreds of publishers and thousands of marketers to serve billions of ads, which led to the acquisition of the company and about 1,000 AppNexians by AT&T, announced earlier today.

I would like to thank Brian and that fantastic, all world, all universe team including Michael Rubenstein, Jon Hsu, Ryan Christensen, Ben John, Catherine Williams, Tim Smith, Nithya Das, Pat McCarthy, Kris Heinrichs, Josh Zeitz, Craig Miller, Tom Shields, Julie Kapsch, Dave Osborn, Doina Harris and many others for allowing Venrock the opportunity to be part of a very exciting journey and a terrific outcome.

And we now look forward to meeting that next “Force of Nature”!