In LinkData, although you can describe properties using a free string, using a generic property that is also commonly used on other sites could possibly improve machine readability for your data.

Basic RDF syntax

Subject
(subject)

Property
(predicate)

Object
(object)

Reference web sites for generic properties are shown below.

Linked Open Vocabularies (LOV)

http://lov.okfn.org/dataset/lov/

The "LOV Search" Features gives you the possibility to search for an existing element (property, class or vocabulary) in the Linked Open Vocabularies Catalogue. It is developed in the framework of the Datalift project and supported by the Open Knowledge Foundation (OKFN).

DBPedia

http://mappings.dbpedia.org/index.php/Main_Page

DBPedia is a project that aims to extract structured information from Wikipedia, to make it available on the Web. You can search for properties that are commonly used as search keywords in this Wiki. (Searching Japanese words is not supported, however.)

Dublin Core (DCMI)

http://dublincore.org/documents/dcmi-terms/

The DCMI (Dublin Core Metadata Initiative) organization is a project to promote the development of standards for representing information on the Web. It has defined many vocabularies to represent bibliographic information such as a web document's contributor, its title, and creation date.

Friend of a Friend (FOAF)

http://xmlns.com/foaf/spec/

As signified by its name, "Friend of a Friend" is a project to express information about people. It defines a vocabulary about people describing a variety of names, regions of interest and home pages, etc.