"What is remarkable about the ISO in this regard is its lack of transparency. Dues are paid, money is raised, merchandise (books, magazines, and newspapers) is sold, but rare is the ISO member who knows that the organization’s 501(c)(3) – the Center for Economic Research and Social Change (CERSC) – bought and sold thousands of dollars in Caterpillar stock in 2010 in spite of the ISO’s support for the Palestinian boycott, divestment, and sanctions (BDS) campaign’s targeting of Caterpillar for selling Israel the bulldozers it uses to demolish Palestinian homes and kill activist Rachel Corrie." - http://www.counterpunch.org/2013/06/24/the-iso-caterpillar-and-democrati...
Oh yeah, the ISO is definitely a business.
It looks like the author of the article have made a progression from being a former ISO member to an actual anarchist. I skimmed through his last article, and he made some decent points.