Internet has opened up so much information for ordinary (/lazy) people like me. One such great resource is the Wikipedia. It has a wealth of information about so many things and it is amazing that all the content was contributed by the millions of visitors themselves. And all the information is provided free-of-charge to the public. The site runs on private donations and is free from advertisements.
Interesting Fact: Since it is totally volunteer contributed effort, Wikipedia rewards hard-workers with Barnstar medals.
Wikis like blogs are helping non-professionals get involved in publishing content onto the internet. I look forward to personal wikis (personal blogs that can be edited by anyone); like a merger of both worlds. Stuart Henshall blogged about this (via Dina).
Wikipedia is maintained by the Wikimedia Foundation. They also maintain other wiki-sites such as Wikinews, Wiktionary, Wikiquote, Wikibooks, Wikisource and the Wikimedia Commons.