Over at my blog at HBR, I made the observation that for many companies, the most difficult competitors to deal with are often not even in their own industries or selling similar products. Instead, it's something their customers covet and will spend scarce resources to obtain, even if it is from some other industry. The blog focuses on a recent Wall Street Journal article that talks about how cell phones are eating up family budgets, squeezing items like restaurants, clothing and other forms of entertainment. So it isn't enough to be ahead of your direct competitors – you need to be more compelling than other industries as well!