Here's a quote from NOM's documents (my emphases)
The strategic goal of this project is to drive a wedge between gays and blacks—two key Democratic constituencies. Find, equip, energize and connect African American spokespeople for marriage; develop a media campaign around their objections to gay marriage as a civil right; provoke the gay marriage base into responding by denouncing these spokesmen and women as bigots. No politician wants to take up and push an issue that splits the base of the party. Fanning the hostility raised in the wake of Prop 8 is key to raising the costs of pushing gay marriage to its advocates and persuading the movement’s allies that advocates are unacceptably overreaching on this issue.
This is what civil rights icon Julian Bond says
"NOM's underhanded attempts to divide will not succeed if Black Americans remember their own history of discrimination. Pitting bigotry's victims against other victims is reprehensible; the defenders of justice must stand together."
Bond also describes this information as evidence of an "evil hand" behind the politics of marriage equality.
This has been picked up by the mainstream as evidence of the hard-ball cynical politics played by NOM. Incidentally, NOM have gone from focusing on opposition to marriage, to general denigration and demonization of LGBT people, which is well-documented over at Equality Matters.
Another morsel in the documents is that they wanted to pay a staffer $50K to find children of LGBT parents who could be put on TV to complain about their upbringing. Stay classy, NOM.