wiki

http://en.wikipedia.org/wiki/Main_Page
you can search million of pages here and you can read the meaning for every word you type here. per day atleast 1000 pages are being added and you can find from technology to books here. all topics are being covered here. if you want to learn about general knowlege to technical you can use this wiki. we can call this one as online dictionary. Most of the worlds languages are covered here. try this one really it is useful one for reading and writing. you can also edit the page if you find wrong in it.