A dataset is great if you want to analyze a large dataset (government data in particular lends itself to this). However, an API allows you to build an applicati

A dataset is great if you want to analyze a large dataset (government data in particular lends itself to this). However, an API allows you to build an application around data that doesn't exist yet: not last year's best seller list, but next week's. If all you had was a way to download the full dataset, the first thing you'd ask for is "a way to download only the stuff that's happened since yesterday". And that's an API.