Public administration, a field that focuses on the organization and implementation of government policies, has been revolutionized by the advent of the internet. Traditional public administration has been significantly transformed by online public administration, thereby improving service delivery and interaction between the government and the public.

One dimension of online public administration involves the application of IT infrastructure to facilitate effective decision-making, policy formulation, and execution. The use of cloud services, databases, and other applications facilitate instant access to relevant data and reports. With this level of accessibility, public administrators can swiftly make informed decisions, which can ultimately save both time and resources.

Further, online public administration fosters transparency and increases access to public services. In this era of digitization, agencies can make the services they offer available online, enhancing accessibility for citizens regardless of their geographical location. Government websites, portals, and social media channels are platforms where citizens can find explanations for various policies, apply for various services, make payments, and even register complaints.

Apart from the aforementioned benefits, online public administration allows for open data. By making data available to the public and engaging with open source communities, governments can spur innovation and encourage civic engagement. These engagements can support problem-solving, foster a sense of community responsibility, and create a mutually beneficial relationship between the public and the government.

Despite its many advantages, there are challenges that face online public administration. It is susceptible to cyber-attacks and must maintain a high level of security to protect sensitive data. Additionally, there is the digital divide issue wherein some citizens lack access to internet services, impairing their ability to capitalize on online public services.

Another challenge is the necessary digital literacy required by both citizens and public administrators to engage effectively online. For optimum effectiveness, educators and government officials must take strides to ensure such literacy is cultivated.

In conclusion, the evolution of online public administration has markedly improved the public sector. It has streamlined operations, improved transparency, and made services more easily accessible to the general public. However, it is essential to address the challenges that come with it, such as cyber-security, the digital divide, and digital literacy in order to fully exploit the benefits of online public administration. Despite these hurdles, we can see the end goal of a more open, efficient, and inclusive public administration sector, leading us to a better understanding of government and public services.