Published Article / The paper reports on a Learn 2.0 technology that was used to support the continuing professional development of mathematics teachers at a secondary school. Design Based Research methods were used within a Multiphase Mixed Methods research framework to create professional development opportunities that were subsequently monitored by Social Network Analysis techniques. We demonstrate that Learn 2.0 technologies can indeed support the continuing professional development of teachers and improve their performance, and also that Social Network Analysis is an effective method to describe, comprehend, clarify and transparently monitor teacher engagement during online professional development activities. We identify 'participation' as a key pre-determinant to success.