1. dispersal from an original homeland to two or more foreign regions;
2. expansion in search of work, in pursuit of trade, or to further colonial ambitions;
3. a collective memory and myth about the homeland, real or imagined;
4. an idealization of the homeland and a collective commitment to its thriving;
5. a movement to return to or at least maintain a connection with the homeland;
6. a strong ethnic group consciousness, maintained over time;
7. a troubled relationship with the host society;
8. a sense of empathy and co-responsibility with co-ethnic members in other countries;
9. the possibility of an enriched creative life in the host country.

And she concludes that in the end the was a diaspora of sorts:

Broadly speaking, however, we might already be able to speculate that for a period the dispersed Scandinavian communities of the Viking Age acted like a diaspora, retaining, synthesizing, and expressing a sense of collective identity and constructing a common cultural discourse, while new circumstances generated innovations and developments which flowed back and forth between them. ‘Diaspora’, then, is arguably not just a buzzword, nor simply a fashionable synonym, but an exploratory concept that offers a new perspective on the Viking Age. Its adoption should give the overseas settlements a greater cultural profile and a more significant role as agents of change, both in their new environments and back home.