Facebook’s initial public offering later this spring will create a billion-dollar windfall for its founders and early investors, so it’s easy to be cynical and view the IPO as another example of insiders cashing in on the latest web phenomenon. But the significance — and symbolism  — of Facebook’s IPO goes much deeper. Facebook’s astonishing rise is an apt metaphor for the emergence over the last two decades of the Internet itself as a tool for individual self-expression and collective organization. It’s also a dramatic example of a generational shift taking place among the entrepreneurial class, one that elevates social change as a priority along with commercial success. Perhaps most importantly, Facebook’s success is a powerful argument to the transformational impact that a free, open Internet can have on society and commerce.

Facebook’s IPO — the largest in Internet history — is a once-in-a-generation milestone in the evolution of the web. It represents a coming-of-age moment for the second major phase in the development of the Internet as a widespread platform: the rise of the social web. In the initial phase, large portals such as America Online and Yahoo established the web as a repository for vast amounts of information. It wasn’t until Google indexed the web with its search engine that this phase reached maturity, allowing users to quickly find information across the Internet, beyond the borders of these centralized communities. But even as Google democratized the web by enabling ordinary people to exercise their voices and become accessible to the broader online world, the Internet remained a largely individualized experience.

(MORE: Read Facebook CEO Mark Zuckerberg’s IPO Letter)

The emergence of social networks like Friendster, MySpace and Facebook gave rise to the second major phase of the web by establishing it as a platform for social interaction. For the first time, these social networks allowed users to establish personal identities on highly-scaled platforms in order to connect and share with others. These services delighted and empowered users by making them feel ownership of their own pieces of digital real-estate, which they could use as personal calling cards to project themselves into cyberspace. Thanks to savvy marketing and engaging design, Facebook caught on like wildfire, first among college students, and later among the public at large. As it grew, Facebook leveraged the network effect of millions of people connected to each other to create an unstoppable momentum that vanquished its social networking foes.

Read more: TIME Business