Basically, where will Big Data real applications are most likely going to happen.
First, to do Big Data, your organization need be be technology mature (big limitation #1). The level of maturity required is mostly available in start-ups or big enterprises. SMB aren't considered because they have no big data problems, no long term vision and little technology maturity in general.
Second, you have to consider the risk of been able to do big data for real (big limitation #2). Most startups don't reach big data due to: founding issue, data issue (not enough) and data availability (privacy constraint).
Once you have the data (enterprise), you are stuck with IT constraints (fear of outsourcing, politics, incompetencies) and data quality (unusable data due to limited integrated QA).
Basically, big data is a dead valley. Big Data is a marketing carrot to attract SMB to invest indefinitely in project that will most likely fail, a failing project will generate more revenue to big data consultant firms. The 2 main places where big data will succeed are in Enterprise like google, amazon, yahoo, nuance and successful startups like facebook, linkedin, twitter. BigData is not a big market, there is too much barrier of entry and the benefits will be destroyed by the complexity of the integration cost. Big data can't succeed if one part of the chain is broken which is the case in 99.9% of the cases.