From this:

A former top deputy to Nation of Islam leader Louis Farrakhan tells Newsmax that Barack Obama's ties to the black nationalist movement in Chicago run deep, and that for many years the two men have had "an open line between them" to discuss policy and strategy, either directly or through intermediaries.

"Remember that for years, if you were a politician in Chicago, you had to have some type of relationship with Louis Farrakhan. You had to. If you didn't, you would be ostracized out of black Chicago," said Dr. Vibert White Jr., who spent most of his adult life as a member and ultimately top officer of the Nation of Islam.

White broke with the group in 1995 and is now a professor of African-American history at the University of Central Florida in Orlando.

White said Obama was "part of the Chicago scene" where Farrakhan, Jesse Jackson, the Rev. Jeremiah Wright Jr. and radicals would go to each other's events and support each other's causes.

"Even though Chicago is the third-largest city in the country, within the black community, the political and militant nationalist community is very small. So it wouldn't be uncommon for [Obama and Farrakhan] to show up at events together, or at least be there and communicate with each other," White told Newsmax...

Note also that Obama, Ayers, and Farrakhan live within just a few blocks of each other in Hyde Park.