yes, exactly, they found a way to monetize a product other than their framework, and they used the OSS framework to draw attention to the non os project. Whether that was deliberate or unintentional, I don't know, but it certainly worked out.

EDIT: I agree with you that the product is good, and that the communication was excellent, but I disagree that the success of ROR was minor to the success of that company. It brought a tremendous amount of attention.