The big promise of big data for marketers is to be able to use all the data we have. By looking at all the information, big data allows us to explore minute details without the risk of blurriness.
in theory, sampling (which always lost detail because it is a proxy for the full data set) and guesswork go away, we can analyse all the data for every customer and prospect, and provide that customer experience nirvana of just the right offer at just the right time.
If that feels like a big change for you, then start small. Attribution, one of the most persistent of marketing challenges, can be a great area to apply big data for immediate results, and ROI.