This new feature allow theme's developers to define settings whose values could be controlled by a new tab inside look-and-feel web interface. It's easy to use. The setting's values will be storen on BD, in the tables: layout or layoutset. It depends of the look-and-feel selected (page or communities). You can assign values to the settings in the Manage Pages / look-and-feel, so you don't have to re-deploy the theme with every change. It will create the velocity variables automatically. It's easy to use:

To define the ThemeWebSetting you must define it inside the liferay-look-and-feel theme's file:

<theme id="id-el-tema" name="nombre-el-tema">
<web-settings>
<setting key="websetting1" value="">
<setting key="webSetting2" value="option1;option2;option3">
...
</web-settings>
</theme>

In the first case, we can assign any value to the setting "websetting1" (it will create a textarea on the web interface): text, html code, etc. In the second ("websetting2"), only "option1", "option2" or "option3" (it will create a combo-list on the web interface).

To use it on the templates: $websetting1 or $websetting2. For example:
if ($websetting2== "option1") {
....