Our API directory now includes 43 metadata APIs. The newest is the OpenStreetMap Taginfo API. The most popular, in terms of mashups, is the Calais API. We list 17 Calais mashups. Below you'll find some more stats from the directory, including the entire list of metadata APIs.
In terms of the technical details, REST and XML lead the way. There are 31 metadata REST APIs and 9 metadata SOAP APIs. Our directory lists 26 metadata XML APIs and 24 metadata JSON APIs.
The most common tags within metadata are 13 metadata search APIs, 9 metadata reference APIs and 5 metadata research APIs.
On the mashup side, we list 1 metadata mashup. We named BBCify as mashup of the day in November.
For reference, here is a list of all 43 metadata APIs.
art.sy API: Artwork information discovery service
Associated Press Metadata API: News content metadata service
Auphonic API: Audio post production service
BibServer API: Bibliographic metadata consolidation and sharing service
Calais API: Semantic data search and extraction service
Cambridge Journals Online API: Cambridge University Press collections
Clear Read API: Article text and metadata extraction tool
Dalet API: Media management service
DCMI Metadata Registry API: Metadata management service
Decibel API: In-depth music metadata
DiscoverEDINA Tagger API: Image metadata service
Fluidinfo API: Online storage and search Platform for metadata
Indian Pincode API: Indian PIN code information service
LibraryCloud API: Aggregated Library metadata delivery service
mEDRA API: European DOI registry
MELT API: German educational Resource search service
mSense API: Metadata generating service
Music Story Pro API: Music metadata database
MusixMatch API: Song lyrics search engine
MyMovies API: Movie and DVD collection management service
NCSU Scholarly Publications Repository API: Academic publication information service
NOAA Historical Observing Metadata Repository API: Historical weather station data service
Nutribu API: Nutrition data for social applications
OCLC Crosswalk API: Metadata translation services
OCLC Virtual International Authority File API: Library authority file service
Ontos API: Semantic data for content
OpenStreetMap Taginfo API: Database of OpenStreetMap location tags
PBS COVE API: PBS video metadata service
PHIN VADS API: Public health terminology service
PLOS Article-Level Metrics API: Usage metrics for PLOS articles
Qobuz API: Streaming/download music service
refbase OpenSearch API: Bibliographic search service
Rutgers University Community Repository API: Digital repository of scholarly articles
Semantics3 API: Product Database
SKOS Thesaurus API: Thesaurus of related concepts
TheGamesDB.net API: Online game artwork and metadata service
Twitlbl API: Twitter data analysis service
Unified Medical Language System API: Medical terminology & taxonomy service
Valobox API: eReader web application for PCs, tablets, and smartphones
Veenome API: Visual data reader for videos
WebKnox Keywords API: Keyword information tool
WebKnox Recipe API: Recipe search engine
WebKnox Web API: Web page processing tool