It's a problem that has long dogged socially responsible businesses. Public companies are legally obligated to maximize returns to shareholders, according to a widespread interpretation of corporate law. For private firms, it's more a matter of withstanding pressure from investors. Hannigan and Marx, for example, fear their social mission could be threatened if an investor changed his mind about Give Something Back's penchant for charity. They want to avoid the fate of ice cream maker Ben & Jerry's, which received a buyout offer from the Dutch conglomerate Unilever (NYSE:UL) in 2000. Founders Ben Cohen and Jerry Greenfield didn't want to sell, so Cohen assembled a group of investors to make a counteroffer. When they couldn't offer as much as Unilever, shareholders sued, and the company, then publicly traded, was forced to relent. In April 2000, Ben & Jerry's was acquired by Unilever for $326 million.Damn - that's no joke. So, should we still buy Ben & Jerry's? I was never into it, but that's still surprising news about Unilever buying them out.