Genealogy is the (last I checked) second most popular search on the internet, right behind porn. That being the case, there are literally thousands of websites that could be of assistance in any one person's search.
Sites commonly used that are not designed for genealogy research include Wikipedia, Library of Congress, National Archives and Records Administration, and social networking sites like Facebook, Twitter and Google +.
During the school year of 2011-2012, I will be leading a family history related project with a group of local Girl Scouts, and we recently held an informational meeting for their parents. I titled our project "The Puzzle of Your Past". Genealogy is just that - a gigantic jigsaw puzzle, and every piece has to fit just right. The same could be said for the numerous websites that exist today. You have to find the right piece at the right time, in order to make the information fit. Some sites, like http://www.ancestry.com/ or http://www.familysearch.org/, you can find a use for just about any time. Others, like a site describing the history of Chaffee County in Colorado, may be so unique it will be used very little in your own research.
That being said, I have volunteered to host two sites on the Trails To The Past network. This is a new genealogy based tree of pages, in which each county in each state has its own site. It's make up is similiar to that of Rootsweb, but only about two years old. I will be hosting Colfax County, Nebraska and Summit County, Colorado. Why did I decide to take on this project? I have so many other things happening in my own research right now, not to mention a two year old running around the house.
The simple answer is I want to share. I want to spread what I have learned about those areas and the people in them, and I want to make it easier for other researchers to find new and diverse information. The student in me says I am doing this for the experience; it will be great for my knowledge base of using the internet, composing pages, and design; as well as a boost in my writing skills and resume. It will definately look good on my BCG application.
Check back in the days to come... these two county sites will be going live, and of course, I will post that to my blog. Also, if you are interested in your own family history, please take a look at Trails To The Past and its family. We're a great bunch of folks!