Oh, it has changed me. It has made me aware that for the most part I live among idiots. Not referring specifically to RIU but there certainly are plenty here. Cynical, yes, in many ways. But then you meet some good people.
The Internet is fundamentally changing human interaction, obviously. The end of the nation-state. That's my opinion.
One more thing. In terms of the mentally ill.... Society's tendency has been to keep these people a bit walled off, usually in basements, institutions, etc. But now days these folks sit online and interact with each other. They reinforce one another's completely whacked out worldviews and publish seemingly reputable looking websites. Weak minded non-mentally ill accept these as news sources. The illness spreads....