The Internet has become a major sales platform, assuming an emergent importance in increasing the economic growth of businesses. Web 2.0 has been a very important change in the way people use the internet and it has created an impact in all sectors of society. This study emphasises the importance of including Web 2.0 tools in online retailing as a contribution for success. The focus of this research lies in Portuguese online retailers and the elaboration of an adoption model for Web 2.0 tools. Through an observation of the 36 most visited Portuguese e-Commerce websites, it was possible to gather information on their adoption patterns of these tools. Social networks, Rich Internet Applications, mashups and Really Simple Syndication were the most popular tools, while semantic search, wikis and blogs were the least implemented. These and other aspects were gathered and then used to build a Web 2.0 adoption model.