It's quite possible that with a different set of circumstances, the problems of spam, porn, black hat SEO, etc. would have triggered a regulatory response that would likely have massively slowed down the growth of the internet.
Imagine FDA-style, mandatory, centralized, single point of failure, pre-market review of every website for "safety" and "efficacy".
That's insane to contemplate, but a few high profile "Myspace child predator" scare stories at the beginning of the internet could very well have made it happen.
Even the very concept of pre-market review is strange to the internet. Here it's accepted that you launch and figure things out iteratively. Part of the reason is that we're more tolerant of visible crashes in computers than other fields.
However, systematic studies (e.g. http://www.marginalrevolution.com/marginalrevolution/2010/12...) have shown that centralized pre-market review even in areas like healthcare costs more lives and money than it claims to save. [Not to digress too much, but among other things, the lack of an opt-out means the FDA has no incentive to remain competent. There are thousands of schools that certify medical doctors, but only one certification agency for medical devices. The relative lack of innovation in healthcare vs. IT is in nontrivial part due to this stifling regulation; see for example what happens when internet culture collides with FDA culture here: http://mobihealthnews.com/6932/interview-the-iphone-medical-...]