I think Quora.com is one of the best website. It is question and answer platform which I used lot of times to get the answers regarding various problems like how to build blog, facebook page etc. Also you can choise which areas question and answers you want i.e feed.
Also it is free platform for writing, you can build your writing. It is very helpful website as you can get guidance from experts and know the experiences of successful peoples and ceo's, celibrities. It covers all topics from psycology to science, astronomy all things. So I think this is best website.