The last company I worked with insisted on using GoogleDocs and Basecamp for all sorts of critical customer information, over my very loud protests. Considering the industry they are in (read: one with some pretty heavy regulation) I was absolutely baffled at this decision. Alas I was over-ruled because it was "cheaper" and "pretty secure". Then again this is a company where the CEO kept a list of passwords on their monitor and never, ever, ever locked their workstation (usually with Outlook prominently displayed and sitting un-watched on a conference table).
I don't have a problem with GoogleDocs (or even, begrudgingly, Basecamp) per se... but it makes me crazy when companies put proprietary and/or sensitive information out on the cloud and don't even consider the security ramifications.