I would like to show a widget in only one page of my site, as i can see it is not possible right?
Should i add that for all my site pages or not?
It depends on where you want to show the widget.
Let’s start with the widget area (sidebar) registration:
This is quite simple. We register a new widget area with some custom markup.
Now we have to show it somewhere. We could add a custom action in our
Or we could use an existing action, this would limit the places where the widget is available. For example the action
For a custom action we’d use instead:
There are several plugins that allow to show widgets based on specific conditions:
An alternative solution is given by the following plugin, which allows you to define a custom set of widgets on a per-page basis, directly from the edit page screen:
It's possible. The easiest way is to use a plugin such as http://wordpress.org/extend/plugins/display-widgets/