Linked from
The 13 pages that link to Exogamy, each with the reason it gives.
ClanRelated: Clan membership can determine which partners are prohibited or preferred.
MatrilinealityRelated: Matrilineal groups may use exogamy to regulate marriage between lineages.
Descent groupRelated: Some descent groups require members to marry outside their own group.
TotemRelated: In some societies, totemic group membership helps determine whom a person may marry.