I don't think the Internet makes people "stupider" I think social networking sites and most forums make people "stupider."
There's a vast amount of knowledge on the Internet and if you surf the Internet on a daily basis and don't learn at least one thing from the Internet in a day you are doing it wrong.
I meant to include this post in my last post so that the post was on topic. Anyway, "knowledge" and "stupid" aren't really opposites of each other. Intelligence and stupid are opposites. Knowing facts isn't a sign of intelligence. Knowing a lot of facts and/or being able to look up facts doesn't make someone any less stupid.
The ability to synthesize those facts, to apply them, understanding them, evaluate them, and use them to determine new facts - that's intelligence. I used to work with mentally retarded adults - severely and profoundly - people who will never be able to live independently, who can't add 5 and 6 at age 35 - that's beyond their abilities, people who have goals to learn the difference between a nickel and a quarter, and it takes them 6 months to be able to identify those two coins correctly. Yet, among them, occasionally there were people who could remember everyone's birthday - they could memorize facts like that. Yet, you could ask them what day today is, and they wouldn't know. "Hey, today is February 8. Whose birthday is today?" Not a clue.
I would argue that the accessibility of the Internet makes people think they're smart, because they have the ability to look up basic facts. I'm not saying though that you can't use the Internet to learn more than just facts.
Oh, and lastly, I think I liked the Internet a lot more before computers became cheap enough for just about everyone to be able to be online. Back when a starter system was a couple thousand dollars, the majority of people online seemed to be those who saw the value of being online. Facebook would be awesome if 80% of the people weren't on it.