This is the best component framework and API available today for building modern web sites and apps. I really enjoy how minimal it is, and powerful at the same time. It removes opinionated development and replaces it with logic and data philosophies, which has in turn fostered a robust and lively code and support community.
Socket.IO has a decent community footprint, including integrations with popular JS frameworks, and has fallbacks to maintain an app's services if websockets are not available for some reason. Websockets are an important factor in most of the web-facing apps I build, to provide asynchronous two-way communication between the app and whatever server or data source it is connected to.