Learning is becoming increasingly self-directed and often occurs away from schools and other formal educational settings. The development of a myriad of new technologies for learning has enabled people to learn anywhere and anytime. Web 2.0 technology allows researchers to shed a new light on the importance and prevalence of informal learning. However, there are few empirical studies that support the claim that this technology facilitates informal learning. The present study investigates the relationship between Web 2.0 levels and the evaluation of informal learning websites. For this purpose, 287 informal learning websites were selected and their Web 2.0 levels were rated based upon eight criteria proposed in the Web 2.0 exploratory literature. In addition, previously examined informal learning evaluation results were employed. The results showed that current informal learning websites have moderately adopted the most heavily promoted features of Web 2.0. Correlation analyses showed a positive relationship between Web 2.0 features and informal learning website ratings. The implications for the relationship and internal correlations of variables were summarized and discussed.