Multiple sites

It seems like one of the cool things to do is to have multiple sites – multiple blogs, multiple photo albums (flickr, picasaweb, etc.)… just all things to all people. Why can’t there be one site that functions as the one site for a person and their identity? What is the requirement to need to set yourself up on multiple sites?

Is it because of the passing fads of social networks? At one time, everyone flocked to MySpace. Now it’s Virb and/or Twitter. Twitter will be a dead fad by the end of the year maybe – what will be the next fad?