Here's something of an idea, don't know how feasible (social networks isn't my specialty): Each 'person' is identified by one or more email addresses. Each pe

Here's something of an idea, don't know how feasible (social networks isn't my specialty): Each 'person' is identified by one or more email addresses. Each person has a network page, which can be hosted anywhere. Messages are sent via RESTful HTTP posts, and can be marked public or private -- public will get posted to the receiver's page by default, private won't be (but there's nothing to stop the receiver from re-posting it to their page, which isn't any different from email). Each person can define groups of friends/contacts by the email addresses of people. This way you can keep friends/family/business separate, even if some people are in more than one group. When you get a public message, you can easily forward it to any of these groups or individual people (or a combination). By default you can ignore messages from people not in any of your groups (the site hosting your page would ignore it right from the HTTP post point). You could also set a specific subpage for messages from people you don't know (aka Formspring.me) Not really sure where the money angle would come in (for whoever hosts the pages).