Arguably the most important decision founders ever make is: who is the first person I should bring into the company? The right answer to that question is very different today than just a few years ago.

Traditionally, founders either hired an engineer to accelerate product development (Microsoft, Amazon, Google, Facebook, Tumblr, Dropbox, etc.) or hired an experienced exec to write a business plan (Apple, Yahoo, Ebay, etc.)

Around 2008, however, something very strange happened. Rather than specialists (in engineering or accounting), startups began hiring generalists as their first employee.

For example, Airbnb's first hire had responsibility spanning operations and product development. Instagram hired a "community manager" to keep users happy. Uber's first employee was hired to be a "business development and product badass." Pinterest's first hire was a jack-of-all-trades who could help wherever he was needed.

What's going on? Why hire a generalist? The answer: today's technology demands it.

The iPhone was introduced in 2007. As a result, technology is now far more pervasive than it was a decade ago and is accelerating the speed at which startups must move from concept to fruition.

Today, startups can't begin with a product and then build a business case. Neither can they start with a business case and then hustle up the product.

Instead, both product and plan must be developed in parallel, which means hiring people who can think without the limited viewpoint inherent in expertise. Generalists make connections between seemingly unrelated disciplines that experts would probably miss.

Here's an infographic from the UK-based job-search firm Adzuna showing how first hire decisions have changed over the years: