Lists of ontologies
There are several webpages that reference ontologies by simply matching a theme (e.g., People, Product) to a URI.
This category requires minimal effort: if the publisher's data are in the domains referenced in the list, the corresponding ontology can readily used.
These lists pose the question "how to define what's in these lists?" Popularity is one aspects, quality may be another. What is a quality ontology? When does it become popular? Who decides?
Description: this website gives a short list of ontologies, classified by themes (People + Organisations, Places, Events, Social Media, Topics + Tags, eCommerce, More...).
Available at: http://semanticweb.org/, bottom right.
Unique strength: concise, straight to the point.
Possible drawback: too simple, too small. Is it maintained? Arbitrary?
Description: it provides links to ontologies, answering simple questions (how about music collections?);
Available at: http://esw.w3.org/VocabularyMarket
Possible drawback: needs cleaning, some old links not valid anymore.
Description: Semanticweb.org has a list of ontologies, ranked according to their usage.
Available at: http://semanticweb.org/wiki/Ontology
Description: A list of ontologies that are fully documented, used by independent data publishers and possibly supported by existing tools.
Available at: Good Ontologies on ESW wiki.
Unique strength: There are well defined criteria for being a member of this list.
Possible drawback: The criteria do not guarantee that the ontologies are good.
Project homepage: http://www.ics.forth.gr/isl/MarineTLO/
Typical prefix: marineTLO:
Description: MarineTLO is a top-level ontology for the marine domain (also applicable to the terrestrial domain).
Which datasets use it: FP7 iMarine Project is using it as an unified and coherent core model for schema mapping among different sources which enables formulating and answering queries which cannot be answered by any individual source.
Tools supporting it: MarineTLO-based Warehouse. It is a warehouse which integrates information coming from FishBase, WoRMS, ECOSCOPE, FLOD and DBpedia. It currently contains information (≈ 3M triples) about marine species (≈ 40,000), ecosystems, water areas, vessels, etc. The warehouse is already in use by various services offered by iMarine and it keeps evolving. (SPARQL endpoint, browsing interface restricted access, Please contact for credentials)
Technicalities: MarineTLO ontology is an ongoing activity and the last version (http://www.ics.forth.gr/isl/MarineTLO/#releases) contains 92 classes and 41 properties. It is represented in OWL 2.