  Web3, the next generation of the Internet, represents a decentralized and
democratized web. Although it has garnered significant public interest and
found numerous real-world applications, there is a limited understanding of
people's perceptions and experiences with Web3. In this study, we conducted an
empirical study to investigate the categories of Web3 application and their
popularity, as well as the potential challenges and opportunities within this
emerging landscape. Our research was carried out in two phases. In the first
phase, we analyzed 200 popular Web3 projects associated with 10 leading Web3
venture capital firms. In the second phase, we collected and examined
code-related data from GitHub and market-related data from blockchain browsers
(e.g., Etherscan) for these projects. Our analysis revealed that the Web3
ecosystem can be categorized into two groups, i.e., Web3 infrastructure and
Web3 applications, with each consisting of several subcategories or subdomains.
We also gained insights into the popularity of these Web3 projects at both the
code and market levels and pointed out the challenges in the Web3 ecosystem at
the system, developer, and user levels, as well as the opportunities it
presents. Our findings contribute to a better understanding of Web3 for
researchers and developers, promoting further exploration and advancement in
this innovative field.
