WordPress widgets are very helpful tools built in to the WordPress.com application. They allow you to arrange the display of content in your blog sidebar, such as your blogroll(s), recent posts, and monthly and category archive lists. With widgets, arrange and display the content in the sidebar of your blog without having to know a single bit of PHP or HTML.
In this case, Widget areas are the regions in your theme that allow you to insert and arrange content (such as a list of your recent blog posts or links to your favorite sites) or custom menus, by dragging and dropping (and editing) available widgets (shown on the WordPress Dashboard's Widget page) into those corresponding areas.
Many widgets offered by WordPress (and those added sometimes by WordPress themes and plugins) provide drag-and-drop installation of more advanced functions normally available only if you wrote code directly into your theme files.
Choose Widgets on the Appearance menu in the Dashboard. The Widgets page displays the available widgets. This feature is a big draw because it lets you control what features you use and where you place them without having to know a lick of code.
To explore the Twenty Ten theme's widget-ready areas, choose AppearanceWidgets on the WordPress Dashboard. The Widgets page displays Primary Widget Area, Secondary Widget Area, First Footer Widget ...