It is widely acknowledged that standards implemented in open source software can reduce the risk for lock-in, improve interoperability, and promote competition on the market. However, there is limited knowledge concerning the relationship between standards and their implementations in open sourcesoftware. This paper reports from an investigation of influences between software standards and open source softwareimplementations of software standards. The study focuses on the RDFa standard and its implementation in the Drupal project. Specifically, issues in the W3C issue trackers for RDFa and theDrupal issue tracker for RDFa have been analysed. Findings show that there is clear evidence ofreciprocal action between RDFa and its implementation in Drupal. The study contributes novel insights concerning effective processes for development and long-term maintenance of software standards and their implementations in open source projects.