The emergence of a knowledge-based and technology-driven economy has prompted adults to seek additional knowledge and skills that will enable them to participate effectively in society. The rapid growth and popularity of the internet tools such as Web 2.0 tools have revolutionized adult learning. Through the rich support of Web 2.0 tools, adult online learning experiences have become social, participatory, authentic, and flexible. Nevertheless, many adult learners have dropped out, withdrawn, or not completed online learning programs. As a result, there is need to understand the experiences, barriers, and motivations associated with adult online learners using Web 2.0 learning technologies to reduce the high dropout rates and promote program completion. Adult learners are different from young learners, and therefore institutions offering online adult education should consider the special characteristics of adult learners in designing online learning environments, as informed by andragogy. The study was conducted using a basic qualitative research approach from an interpretive philosophical perspective. Data for the study was collected using semi-structured interviews conducted with 20 purposively selected adult online learners who used Web 2.0 tools. Qualitative data analysis followed three steps including reducing data, displaying data, and drawing and verifying conclusions. Participants' description of online learning with Web 2.0 tools showed that the tools appropriately addressed the needs of adult learners; allowed learners to learn at their own pace; and enhanced collaborative learning experiences. The findings further show that although Web 2.0 tools are consistently decreasing the traditional barriers associated with distance education, adult learners continue to experience difficulties in online learning. Barriers identified included insufficient social interactions, lack of technical skills, and organizational, institutional, and family-related barriers. Participants cited self-development, convenience, and accessibility of the Web 2.0 learning technologies as the most important sources of motivation enabling them to persist. The findings have important implications for the practice of adult online education and future adult online learning research. [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/en-US/products/dissertations/individuals.shtml.]