Public administration research strongly supports the argument for administrator-citizen collaborations and shows that Web 2.0 social media tools have the potential to increase these collaborations. Some public managers have fully embraced the adoption of social media tools to their fullest collaborative potential while other managers have chosen to limit their full collaborative potential. This study examines four environmental influences to determine if they are the cause of the diverse levels of social media adoption among public administrators. A survey of 157 department managers from 261 large cities across the U.S. shows that 82% of the respondents are currently using some form of social media tools to engage citizens. The results show that perceived organizational influences and perceived administrator preconceptions of social media tools are having the greatest impact on the respondents' decision to adopt social media. Provided that response rate bias is not occurring in this study, there are two possible explanations for the results. One possible explanation is that Web 2.0 social media adoption may be following a similar path as the adoption of earlier forms of Web 1.0 e-government tools. The other possible explanation is that managers may be operating within a rational environment when deciding whether or not to adopt Web 2.0 social media tools.