Freebase and DBPedia are both community supported semantic databases of content. However, on one hand Freebase is curated for people, places, and things. While, DBPedia takes most of the information from Wikipedia. The two databases are now interlinked in a linked data albeit in partial set of topics. However, their approach is different. Freebase utilizes the Meta Query Language as a customized option whereas DBPedia supports SPARQL. DBPedia also has a large academic community with other side semantic based projects, whereas Freebase is owned by Google. Most such databases in order to be classed as open data need to share a very open license policy on data. The choice of which one to use depends entirely on one's application needs. The curated data may be different across the two databases based on the data sources. In fact, even Freebase uses data extractions from Wikipedia. They both have different goals, schemas, and identifiers. Freebase perhaps is more diverse in its use of data sources. Freebase also makes it freely accessible to users to curate the data. However, in order for one to get an update on DBpedia, they would have to first update it on Wikipedia. Even the structure of data storage can be slightly different. Freebase is based on n-tuples whereas DBPedia is based on RDF. Freebase is more in tune with the open data community whereas DBpedia tries to follow the strict approaches of the Semantic Web. Even the tool development is mostly via third-party for DBPedia, but mostly from Google on Freebase as well as the user community. One could utilize both in a linked data to build meshable vocabularies, taxonomies, thesauri, or even topic maps.
