The blogger TexasDarlin is developing the idea that Obama became associated with Bill Ayers while Obama was studying at Columbia University in Manhattan during 1981-83. During that same period Ayers, who had dropped out of the Weather Underground in 1980, was studying at Bank Street College of Education, also in Manhattan. Ayers earned a Master’s Degree from that school in 1984 and then a Doctorate from Columbia in 1987. After 1987, Obama and Ayers both were living in Chicago, which is where their known associations begin.

http://texasdarlin.wordpress.com/2008/09/12/obamas-ties-to-ayers-back-to-high-school/#more-2964