However, there do exist a small proportion (i.e., on average 4.94% per Web API) of discussions of a Web API that are persistent concerns and disappear slowly. Exceptionally, a majority of discussions of some Web APIs are persistent concerns and disappear slowly. For example, a majority of discussions (i.e., 77.5%) for Facebook API are persistent concerns and disappear slowly. It implies that Facebook team is either not aware of the discussed topics or does not quickly address the concerns.