The bulk of the donations came from the Service Employees International Union (SEIU), which contributed $7.4 million between 2005 and 2008 to the national organization, state chapters and allied groups. SEIU’s single largest donation of $1.5 million went to the ACORN Community Labor Organizing Center (ACLOC) in 2006. SEIU also made a $1.3 million donation to ACORN International in 2005.
The United Food and Commercial Workers (UFCW), the Longshore and Warehouse Union, the Communication Workers of America (CWA), and the National Education Association (NEA) were other top contributors.
SEIU Locals 100 and 880 were listed as allied organizations on ACORN’s web site until The Examiner highlighted this connection.

Why would unions pay 10 million dollars to a group of community organizers?

I need more sleep, because I read this clip title as "Unicorns give ACORN nearly $10 million dollars."

I thought.. so that is the story now? Unicorns?

Funny! actually I like your title better.