Why SeattleWiki?
Check out the Why SeattleWiki? page. You can also read this blog post by one of the SeattleWiki organizers.
How can I help organize a SeattleWiki meetup?
Check out the organizing resources page and the SeattleWiki meetups page.
Who maintains SeattleWiki?
This is a Code for Seattle project. There are many other Code for Seattle projects, and you're invited to get involved!