Those libraries are ultimately just more sophisticated versions of this on a bigger scale. Meteor in particular takes reactivity to a whole new level: changes a

Those libraries are ultimately just more sophisticated versions of this on a bigger scale. Meteor in particular takes reactivity to a whole new level: changes are propagated immediately not only to you but to other users as well (if appropriate to the application, e.g., a chat room). The philosophy is more or less the same in all cases: make the page react immediately to what the user is doing without a full refresh. Some of those libraries take it further and tie the page directly to the application back-end or database if desired. I think the main appeal of something like Tangle is to get the benefits of reactive programming while using only a very lightweight and simple library. It provides a very clean interface to a subset of the functionality.