Where does Wikipedia rank statistically? (question purposely vague)
Justin Bailey may have answered your question with the #8 statistic, but here’s another that you may find interesting: In 2009, Wikipedia commanded 97% of the online encyclopedia market share. The proportions have obviously changed since then, but that still gives a good idea of how completely and totally Wikipedia dominates the interwebs.
I’m fairly clueless about how Wikipedia works. You edit and write articles? Do you do this for fun or are you being paid?
I was fairly clueless about how Wikipedia works before I started editing, so you’re definitely not alone! There are lots of different ways that people can contribute: content writing, peer review, copyediting, bot creation and maintenance, WikiProject organization, vandalism fighting, dispute resolution, images and media, new user mentorship, new page patrol, Articles for Deletion discussions, and so on and so forth. Some people choose highly specialized roles for themselves (checking hyphens and dashes, writing about mushrooms, etc.), while others like to keep it fresh by engaging a whole bunch of different activities.
The most important thing to know is that all of those tasks are completed entirely by volunteers. We are not paid by the Wikimedia Foundation (WMF), we can choose to do any kind task that we want as long as we’re not assholes, we can retire or take breaks whenever we feel like it, and we are not required to divulge any information about our real identities – name, occupation, credentials, whatever. There is a small staff that works for WMF, and most of them have Wikipedia accounts, but none of their job responsibilities involve content editing – it’s mostly stuff like server maintenance, public outreach, fundraising, etc.
What determines what you write and what you edit?
Sometimes what I write about is determined by what sources I have available. I happen to have a massive encyclopedia of theater biographies, so from time to time I’ll crank out articles about obscure actors just for fun. Sometimes I work on improving Wikipedia’s coverage of an area that I’m already fairly knowledgable about, such as gamma-ray bursts. Sometimes I work on articles that I know absolutely nothing about, like the CSI effect, simply because it’s a fascinating and exciting process to learn and teach others all at the same time. Sometimes I get asked to review or collaborate on someone else’s work because they want an objective view from someone who isn’t familiar with the sources at all.
I hope this clears things up a bit for you. If not, feel free to ask more specific questions.