The RadTagCloud is the Tag Cloud control that is packed with the Sitefinity SDK (Software Development Kit). It could be used for displaying links in a TagCloud-like fashion. These items could be managed by the user in the Sitefinity backend, in the same way as with other widgets: by their public properties.
The RadTagCloud could be put in a markup file, like a usercontrol.
<telerik:RadTagCloud ID="RadTagCloud1" runat="server" />