*This is pretty out of date, as of 2/25/2019 DNN v9.2
The Telerik RadEditor isn't even part of the latest DNN release and the FCKhtmlEditor, from what I can tell, is now the CKEditor. The default editor that comes with DNN (DNNConnect.CKE) is not very good, but you can download an updated or better version (not sure if they are related) of the CKEditor from here - https://github.com/w8tcha/dnnckeditor
One of the strengths of DotNetNuke is the ability to modify the Providers and swap out functionality on a large scale with ease. A common change is to modify the HTML Provider, this page shows you how to do so.
If you are on DotNetNuke 5.4+ and have upgraded from a previous version of DNN you are likely still using the FCK Editor, you can enable the new Telerik Rad Editor provider by following the instructions below.
Enabling the Telerik RAD Editor in DNN requires you to make a simple change to the DotNetNuke web.config file that can be found in the root of your website on the file system. When you open the file up find the following section of the web.config file
You will need to change the defaultProvider=”FckHtmlEditorProvider” setting to be defaultProvider=”TelerikEditorProvider”
Once you’ve done that simply save the changes to the web.config file and reload your website! Then any modules that use the standard DNN text editor control should be using Telerik instead of FCK.
SourceThis entry is based on the blog post at DNNDaily.com