I'll bet you they will get more out of this than diaspora in the long run.
There is an interesting Jewish sub-theme to all this, Diaspora being obviously a term with a strong connection to the Jewish faith, most or all of these four are from Jewish heritage and Zuckerberg himself is too.
I think their Jewish background is what caused them to pick it, not because they relate it to African, Greek or Irish events.
Also, the allusion is more recognizable in the niche of early adopters they need to court for traction. That's a signal that they'll be less mass-market (connotations: more hip, less tacky) than FB has become recently.
A large number of people leaving their 'home'.
I've seen worse metaphors.