Citizens' engagement on local governments' Facebook sites. An empirical analysis: The impact of different media and content types in Western Europe

Useful for background. Argues why Twitter is used instead of another media outlet.
Also provides a model for my own study on how to categorize

What it does.
"This study provides practitioners and academics with some initial research findings about the effect of different communicational strategies on citizen engagement, which are very important factors in order to improve the effectiveness of e-participation offerings."

Findings:
"Different media and content types have a significant impact on citizens' engagement.
•Communicational differences across public administration styles exist.
•Local governments allowing wall posts obtain higher engagement levels.
•A bigger audience does not necessarily result in larger engagement levels.
•Posts have to be focused around topics of interest to local citizens.
•SM are helping to empower citizens and expand democracy."