The various uses of a wiki page

You want to get information about anything? What is the first way that comes to your mind? I don’t know about others but I use google search. Now, whenever I make a search on google regarding something the top few results are always articles or pages from Wikipedia. So, the basic use of a wiki page is to provide information. It is also known as the most cost efficient way of marketing because the Wikipedia page price for creation is very affordable. Businesses all over the world use wiki pages as a means to engage their target audience and to increase their reach. What other uses do you think are there?