When you want to transform your cell values from simple strings to URLs, different choices are possible. After all, a given concept can be identified with many URLs as there are many pages on the Web about the same topic. This need not be a problem as long as each URL unambiguously identifies a single concept. However, we must choose which URL we want to use. On the Web, there are many databases of concepts, the most well-known being Wikipedia. In addition to databases for humans, there are also several databases targeted at machines. One example is Freebase, a collaborative knowledge base in which machine-readable facts about virtually every topic are stored.
Note
Before OpenRefine was called Google Refine, it was owned by Freebase creator MetaWeb and called Freebase Gridworks. As a tool for manipulating large datasets, it fitted nicely in the Freebase philosophy of making structured data available.
Therefore, we will reconcile our cell values with...
