Bubble should provide small communities with a place to securely communicate, organize, and exist on the web.
From the blog post explaining idea behind the project:
I've begun exploring an idea: what would it mean to create a community platform that was anti-viral; that is, committed as a core principle to having useful boundaries within which something healthy can grow undisturbed. Want ads? No problem. Want to organize a group, publish a manifesto, plan events, and send direct messages? Go for it. Want to invite 6 billion people into one space? Not so fast.
Smaller things have many advantages: higher social capital, lower volatility, simpler design, etc.
If it's simple, it will be easier to build, easier to understand, and easier to use.
If you can't trust it, what's the point?