Merlot
Content 
A review rating process combined with an easy-to-use and free database structure allows faculty to easily locate high-quality digital learning materials with evaluations and guidance for use.
Selection 
MERLOT stands for the Multimedia Educational Resource for Learning and Online Teaching. It's an international consortium of partners and affiliates which operate since 1997 as an initiative of The California State University Center for Distributed Learning. Content selection and evaluation is operated on a discipline-community basis
Format
Infos are highly structured in a complex and rich metainfo design. Materials are classified according to their format, nature and scope (testing, workbook, concept visual representation, power point exposition)
Information density
Merlot is a growing open source collection of over 17,000 materials, web-based learning materials, each one selected, classified and often reviewed
Content Pertinence to Political Science
Under the Social Sciences domain with its over 1530 learning materials, PS related online sources are about 95
Updating Rate
Content is very often updated from various contributing sources