The World Bank posts this definition of e-government: “...the use by government agencies of information technologies (such as Wide Area Networks, the Internet, and mobile computing) that have the ability to transform relations with citizens, businesses, and other arms of government. These technologies can serve a variety of different ends: better delivery of government services to citizens, improved interactions with business and industry, citizen empowerment through access to information, or more efficient government management. The resulting benefits can be less corruption, increased transparency, greater convenience, revenue growth, and/or cost reductions."
The following links are examples of e-government at local, state, national, and international government levels:
Measuring e-Government Efficiency by 
E-Government: Information, Technology, and Transformation by 
E-Government Implementation, Adoption and Synthesis in Developing Countries by 
Governing electronically : e-government and the reconfiguration of public administration, policy and power by Best of the Web Awards are given annually by Center for Digital Government and Government Technology. In its 20th year, the annual Best of the Web (BOW) awards recognize city, county and state governments for outstanding portals and websites based on innovation, functionality, productivity and performance. 2015 first-place BOW winners are the City of Independence, Missouri; Sacramento County, California; and the State of Arkansas in the state category, a first-place winner also in 2011.
What do the Best Government Websites have in Common? "The best government websites tend to use simple, high-image, low-text designs; prioritize accessibility and mobility; prominently feature a search function; and start with a design philosophy that puts the user first. These elements have long been cornerstones of good design."