It's a distribution channel - one where all the cool kids currently hang out. He could also be on G+ and Facebook and Twitter and Quora and Reddit and MySpace..

It's a distribution channel - one where all the cool kids currently hang out. He could also be on G+ and Facebook and Twitter and Quora and Reddit and MySpace...and...and... The technology of each is basically irrelevant if there is an attractive audience, as all of us participating on this site clearly demonstrates.