I saw the film The Social Network last night. Fact or fiction, the film tells the story of a few Harvard students who came up with an idea at about the same time. One of them turned the idea into Facebook and became a billionaire at the ripe old age of 23. Others did not, and cried foul.

As I watched, I couldn’t help thinking back to another Harvard kid with an idea: Me. In 1996, I launched a website called BranchOut with a friend from college. It was an online social network, initially exclusive to Ivy Leaguers, and later opened to others. Around the same time, several other startups launched similar sites. None of them became Facebook.

The film triggered a lot of emotions. I felt inspired to go build the next big thing, and envious of that “we’ve struck oil!” feeling.

One thing I did NOT feel was that someone had stolen “my” idea. That’s because the initial idea for a startup is nearly worthless. The real value comes with evolution. That requires experimenting, measuring  results, and pivoting. The Zuckerberg character started with the idea of profiles. Then added relationship status, friending and walls. He limited admission to Harvard, then expanded gradually. He tried ads. First they didn’t work. Later they did. And so on.

Another thing I didn’t feel was guilt. That’s because context is a huge driver of startup success. In 1996, consumers were using dialup, so they couldn’t easily upload photos. People were wary about sharing their information online. And message boards and private email systems were relatively new challenges for programmers. All of that and more needed to change for Facebook to flourish.

So pay close attention to your environment before starting a company, and don’t hold on to your first kernel of an idea too tightly.