Widgets - Create vs Add

Widgets are small snippets of code that one can embed in their website (manually insert the snippet code in their website's source code).

While any Tom, Dick, Harry can 'Add' a widget (multiple widgets) on their sites, it is a totally different ballgame how a publisher provides data to widget call coming from such users.

I wanted to get into the technical details of how a widget is 'Created' by the provider and found this link a very interesting read.
How to build a web widget