Abstract: Computer-storage media, systems, and methods for facilitating development of web pages with cross-communicating tags are provided. The libraries and controls do not require a page transition or refresh operation to update information or instantiate features because the tags subscribe to a server for the information supplied to them. The update information can be requested by a first set of tags or pushed by a second set of tags. A package available online to developers includes development components for execution as part of a web page. These applications utilize APIs and a set of tags that are at least a portion of a markup language library. The tags are for initiating and executing web features, including instant messaging features. There is a developer interface to code the web page with the web application.