This dissertation study investigates the mathematics education communities participating Twitter conversation using #MTBoS and #iteachmath hashtags. The mixed methods study answers following two research questions by using social network analysis and content analysis: "Who are the people fostering mathematics education conversation on Twitter through #iteachmath and or #MTBoS hashtags?" "What kind of content do people participating in the mathematics education communities on Twitter using #iteachmath and or #MTBoS share on the platform?" Along with answering the two research questions, the study also makes methodological contributions in how to collect and analyze social media data coming from Twitter for mixed method studies in educational research. The study was conducted on Twitter with publicly available data. The data analyzed for this study were the tweets that included two hashtags: #MTBoS and or #iteachmath and were retweeted between October 1st and October 15th by the Twitter Bot (personalizedCo). Later Twitter Standard API was used to collect the information about users. The study found out that the community around #MTBoS and #iteachmath mirrors some of the characteristics of the affinity space and the community serves as a resource for the educators in various ways: sharing learning resources, pedagogical support, asking questions both related to subject matter or related to teaching practices and networking. At the end, the study makes recommendations on how to look at the same community from different angles to expand our understanding of the community and its participants. [The dissertation citations contained here are published with the permission of ProQuest LLC. Further reproduction is prohibited without permission. Copies of dissertations may be obtained by Telephone (800) 1-800-521-0600. Web page: http://www.proquest.com.bibliotheek.ehb.be/en-US/products/dissertations/individuals.shtml.]