I have an idea for a collaborative/shared marketplace for a niche product (think airbnb, but for other niche) and is currently building a prototype, but is confused on how to get the very early user for the site to function. I know how user #1 experience is crucial and how del.ico.us was started as a personal bookmarking site, but how does airbnb, craiglist, and many social site gain traction?
Many thanks for the help.