What are the motives of people filling Wikipedia with background information?

Question

MediaWiki

Hello.
I am interested in this model, when people who do not know each other collectively work on one article. I understand that they are united by the idea of ​​writing an article on a topic of interest, but I don’t understand why they don’t pass by (a critical mass has been reached or something more)? And what percentage of people remain active wiki contributors? What incentives still move you to stay in the community, maybe there are achievements like ranking and you want to grow up in your eyes? Something else?
Question to all who govern Wikipedia (call familiar Wikipedians in the question, if any). Plus, I'm wondering - are there studies or books on this topic (incentives specifically)? By the way, I read "Wikinomics" - a cool book.
I believe that the topic affects many areas of the Internet (the same comments on Habré), and therefore it will be of interest not only to me.
I will be incredibly grateful for help in unwinding this tangle of my misunderstanding.

Answer 1

And I sincerely do not understand what exactly you do not understand. Sharing knowledge is imperative. Here you have a clear imperative - "me". There are others, even if you don't believe it. For example, the desire for self-expression. And the acquired benefits have nothing to do with it (although they are useful).

Answer 2

Well, for example, if you are a copywriter and at the same time your article gets into Wikipedia - it’s very, very not bad for a portfolio, I think) Well, there can also be many motives and factors here - the usual desire to share information and knowledge is in the first place, here as for me)

Answer 3

Perhaps then people can throw a link in the resume.