The wait is finally over. After years of anticipation and weeks of headlines, the world’s largest social network is a publicly-traded company.

FB shares, which priced at $38 yesterday, became available to the general public in the past hour on the NASDAQ.

After a delay, the stock hit the market at a opening price of $42.05. It is currently trading at around $40.

Facebook’s IPO is a huge milestone for a company that is arguably unlike any other to come before it. Launched in 2004 from a university dorm room, Facebook has risen to become more than just a multi-billion dollar consumer internet star — it’s a cultural phenomenon used by close to a billion people.

But the company’s public debut is hardly the end of the story Mark Zuckerberg wrote. Instead, it’s just the beginning of what could prove to be either one of the greatest tech investment opportunities ever or a passing fad that brought irrational exuberance back to internet stocks. Which one will it be? Naturally, it depends on who you ask.

On one hand, Facebook is a force to be reckoned with. It has nearly a billion users, billions in revenue, one of the best-recognized brands in the world and some of the best engineering talent in Silicon Valley. Facebook boosters thus argue that the company is just getting started and its best days are ahead of it.

On the other hand, Facebook’s current valuation is based on its potential more than its relatively modest earnings and faces significant challenges in realizing all of its potential, including mobile. Skeptics will point out that the company is no spring chicken, saw a quarter-over-quarter revenue decline last quarter and that key insiders are selling in the IPO, hinting that they may believe Facebook’s valuation has peaked (or is close to peaking).

One thing is for sure: the initial movement in FB shares (up or down) in the next hours, days and weeks will make for great entertainment, but it’s what happens in the coming months and perhaps even years that will determine whether Facebook is the next Google, or the next Groupon.